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2025-02-21riscv: KVM: Remove unnecessary vcpu kickBillXiang
Remove the unnecessary kick to the vCPU after writing to the vs_file of IMSIC in kvm_riscv_vcpu_aia_imsic_inject. For vCPUs that are running, writing to the vs_file directly forwards the interrupt as an MSI to them and does not need an extra kick. For vCPUs that are descheduled after emulating WFI, KVM will enable the guest external interrupt for that vCPU in kvm_riscv_aia_wakeon_hgei. This means that writing to the vs_file will cause a guest external interrupt, which will cause KVM to wake up the vCPU in hgei_interrupt to handle the interrupt properly. Signed-off-by: BillXiang <xiangwencheng@lanxincomputing.com> Reviewed-by: Andrew Jones <ajones@ventanamicro.com> Reviewed-by: Radim Krčmář <rkrcmar@ventanamicro.com> Link: https://lore.kernel.org/r/20250221104538.2147-1-xiangwencheng@lanxincomputing.com Signed-off-by: Anup Patel <anup@brainfault.org>
2025-02-17riscv: KVM: Fix SBI sleep_type useAndrew Jones
The spec says sleep_type is 32 bits wide and "In case the data is defined as 32bit wide, higher privilege software must ensure that it only uses 32 bit data." Mask off upper bits of sleep_type before using it. Fixes: 023c15151fbb ("RISC-V: KVM: Add SBI system suspend support") Signed-off-by: Andrew Jones <ajones@ventanamicro.com> Reviewed-by: Anup Patel <anup@brainfault.org> Link: https://lore.kernel.org/r/20250217084506.18763-12-ajones@ventanamicro.com Signed-off-by: Anup Patel <anup@brainfault.org>
2025-02-17riscv: KVM: Fix SBI TIME error generationAndrew Jones
When an invalid function ID of an SBI extension is used we should return not-supported, not invalid-param. Fixes: 5f862df5585c ("RISC-V: KVM: Add v0.1 replacement SBI extensions defined in v0.2") Signed-off-by: Andrew Jones <ajones@ventanamicro.com> Reviewed-by: Anup Patel <anup@brainfault.org> Link: https://lore.kernel.org/r/20250217084506.18763-11-ajones@ventanamicro.com Signed-off-by: Anup Patel <anup@brainfault.org>
2025-02-17riscv: KVM: Fix SBI IPI error generationAndrew Jones
When an invalid function ID of an SBI extension is used we should return not-supported, not invalid-param. Also, when we see that at least one hartid constructed from the base and mask parameters is invalid, then we should return invalid-param. Finally, rather than relying on overflowing a left shift to result in zero and then using that zero in a condition which [correctly] skips sending an IPI (but loops unnecessarily), explicitly check for overflow and exit the loop immediately. Fixes: 5f862df5585c ("RISC-V: KVM: Add v0.1 replacement SBI extensions defined in v0.2") Signed-off-by: Andrew Jones <ajones@ventanamicro.com> Reviewed-by: Anup Patel <anup@brainfault.org> Link: https://lore.kernel.org/r/20250217084506.18763-10-ajones@ventanamicro.com Signed-off-by: Anup Patel <anup@brainfault.org>
2025-02-17riscv: KVM: Fix hart suspend_type useAndrew Jones
The spec says suspend_type is 32 bits wide and "In case the data is defined as 32bit wide, higher privilege software must ensure that it only uses 32 bit data." Mask off upper bits of suspend_type before using it. Fixes: 763c8bed8c05 ("RISC-V: KVM: Implement SBI HSM suspend call") Signed-off-by: Andrew Jones <ajones@ventanamicro.com> Reviewed-by: Anup Patel <anup@brainfault.org> Link: https://lore.kernel.org/r/20250217084506.18763-9-ajones@ventanamicro.com Signed-off-by: Anup Patel <anup@brainfault.org>
2025-02-17riscv: KVM: Fix hart suspend status checkAndrew Jones
"Not stopped" means started or suspended so we need to check for a single state in order to have a chance to check for each state. Also, we need to use target_vcpu when checking for the suspend state. Fixes: 763c8bed8c05 ("RISC-V: KVM: Implement SBI HSM suspend call") Signed-off-by: Andrew Jones <ajones@ventanamicro.com> Reviewed-by: Anup Patel <anup@brainfault.org> Link: https://lore.kernel.org/r/20250217084506.18763-8-ajones@ventanamicro.com Signed-off-by: Anup Patel <anup@brainfault.org>
2024-12-30RISC-V: KVM: Add new exit statstics for redirected trapsAtish Patra
Currently, kvm doesn't delegate the few traps such as misaligned load/store, illegal instruction and load/store access faults because it is not expected to occur in the guest very frequently. Thus, kvm gets a chance to act upon it or collect statistics about it before redirecting the traps to the guest. Collect both guest and host visible statistics during the traps. Enable them so that both guest and host can collect the stats about them if required. Reviewed-by: Anup Patel <anup@brainfault.org> Signed-off-by: Atish Patra <atishp@rivosinc.com> Link: https://lore.kernel.org/r/20241224-kvm_guest_stat-v2-3-08a77ac36b02@rivosinc.com Signed-off-by: Anup Patel <anup@brainfault.org>
2024-12-30RISC-V: KVM: Update firmware counters for various eventsAtish Patra
SBI PMU specification defines few firmware counters which can be used by the guests to collect the statstics about various traps occurred in the host. Update these counters whenever a corresponding trap is taken Reviewed-by: Anup Patel <anup@brainfault.org> Signed-off-by: Atish Patra <atishp@rivosinc.com> Link: https://lore.kernel.org/r/20241224-kvm_guest_stat-v2-2-08a77ac36b02@rivosinc.com Signed-off-by: Anup Patel <anup@brainfault.org>
2024-12-30RISC-V: KVM: Redirect instruction access fault trap to guestQuan Zhou
The M-mode redirects an unhandled instruction access fault trap back to S-mode when not delegating it to VS-mode(hedeleg). However, KVM running in HS-mode terminates the VS-mode software when back from M-mode. The KVM should redirect the trap back to VS-mode, and let VS-mode trap handler decide the next step. Signed-off-by: Quan Zhou <zhouquan@iscas.ac.cn> Reviewed-by: Anup Patel <anup@brainfault.org> Signed-off-by: Atish Patra <atishp@rivosinc.com> Link: https://lore.kernel.org/r/20241224-kvm_guest_stat-v2-1-08a77ac36b02@rivosinc.com Signed-off-by: Anup Patel <anup@brainfault.org>
2024-12-30RISC-V: KVM: Allow Ziccrse extension for Guest/VMQuan Zhou
Extend the KVM ISA extension ONE_REG interface to allow KVM user space to detect and enable Ziccrse extension for Guest/VM. Signed-off-by: Quan Zhou <zhouquan@iscas.ac.cn> Reviewed-by: Andrew Jones <ajones@ventanamicro.com> Link: https://lore.kernel.org/r/d10e746d165074174f830aa3d89bf3c92017acee.1732854096.git.zhouquan@iscas.ac.cn Signed-off-by: Anup Patel <anup@brainfault.org>
2024-12-30RISC-V: KVM: Allow Zabha extension for Guest/VMQuan Zhou
Extend the KVM ISA extension ONE_REG interface to allow KVM user space to detect and enable Zabha extension for Guest/VM. Signed-off-by: Quan Zhou <zhouquan@iscas.ac.cn> Reviewed-by: Andrew Jones <ajones@ventanamicro.com> Link: https://lore.kernel.org/r/4074feb27819e23bab05b0fd6441a38bf0b6a5e2.1732854096.git.zhouquan@iscas.ac.cn Signed-off-by: Anup Patel <anup@brainfault.org>
2024-12-30RISC-V: KVM: Allow Svvptc extension for Guest/VMQuan Zhou
Extend the KVM ISA extension ONE_REG interface to allow KVM user space to detect and enable Svvptc extension for Guest/VM. Signed-off-by: Quan Zhou <zhouquan@iscas.ac.cn> Reviewed-by: Andrew Jones <ajones@ventanamicro.com> Link: https://lore.kernel.org/r/133509ffe5783b62cf95e8f675cc3e327bee402e.1732854096.git.zhouquan@iscas.ac.cn Signed-off-by: Anup Patel <anup@brainfault.org>
2024-12-30RISC-V: KVM: Add SBI system suspend supportAndrew Jones
Implement a KVM SBI SUSP extension handler. The handler only validates the system suspend entry criteria and prepares for resuming in the appropriate state at the resume_addr (as specified by the SBI spec), but then it forwards the call to the VMM where any system suspend behavior may be implemented. Since VMM support is needed, KVM disables the extension by default. Signed-off-by: Andrew Jones <ajones@ventanamicro.com> Reviewed-by: Anup Patel <anup@brainfault.org> Link: https://lore.kernel.org/r/20241017074538.18867-5-ajones@ventanamicro.com Signed-off-by: Anup Patel <anup@brainfault.org>
2024-12-06RISC-V: KVM: Fix csr_write -> csr_set for HVIEN PMU overflow bitMichael Neuling
This doesn't cause a problem currently as HVIEN isn't used elsewhere yet. Found by inspection. Signed-off-by: Michael Neuling <michaelneuling@tenstorrent.com> Fixes: 16b0bde9a37c ("RISC-V: KVM: Add perf sampling support for guests") Reviewed-by: Atish Patra <atishp@rivosinc.com> Reviewed-by: Anup Patel <anup@brainfault.org> Link: https://lore.kernel.org/r/20241127041840.419940-1-michaelneuling@tenstorrent.com Signed-off-by: Anup Patel <anup@brainfault.org>
2024-11-27Merge tag 'kvm-riscv-6.13-2' of https://github.com/kvm-riscv/linux into HEADPaolo Bonzini
KVM/riscv changes for 6.13 part #2 - Svade and Svadu extension support for Host and Guest/VM
2024-11-27Merge tag 'riscv-for-linus-6.13-mw1' of ↵Paolo Bonzini
git://git.kernel.org/pub/scm/linux/kernel/git/riscv/linux into HEAD RISC-V Paches for the 6.13 Merge Window, Part 1 * Support for pointer masking in userspace, * Support for probing vector misaligned access performance. * Support for qspinlock on systems with Zacas and Zabha.
2024-11-21RISC-V: KVM: Add Svade and Svadu Extensions Support for Guest/VMYong-Xuan Wang
We extend the KVM ISA extension ONE_REG interface to allow VMM tools to detect and enable Svade and Svadu extensions for Guest/VM. Since the henvcfg.ADUE is read-only zero if the menvcfg.ADUE is zero, the Svadu extension is available for Guest/VM and the Svade extension is allowed to disabledonly when arch_has_hw_pte_young() is true. Signed-off-by: Yong-Xuan Wang <yongxuan.wang@sifive.com> Reviewed-by: Andrew Jones <ajones@ventanamicro.com> Reviewed-by: Samuel Holland <samuel.holland@sifive.com> Acked-by: Palmer Dabbelt <palmer@rivosinc.com> Link: https://lore.kernel.org/r/20240726084931.28924-4-yongxuan.wang@sifive.com Signed-off-by: Anup Patel <anup@brainfault.org>
2024-11-11Merge patch series "Zacas/Zabha support and qspinlocks"Palmer Dabbelt
Alexandre Ghiti <alexghiti@rivosinc.com> says: This implements [cmp]xchgXX() macros using Zacas and Zabha extensions and finally uses those newly introduced macros to add support for qspinlocks: note that this implementation of qspinlocks satisfies the forward progress guarantee. It also uses Ziccrse to provide the qspinlock implementation. Thanks to Guo and Leonardo for their work! * b4-shazam-merge: (1314 commits) riscv: Add qspinlock support dt-bindings: riscv: Add Ziccrse ISA extension description riscv: Add ISA extension parsing for Ziccrse asm-generic: ticket-lock: Add separate ticket-lock.h asm-generic: ticket-lock: Reuse arch_spinlock_t of qspinlock riscv: Implement xchg8/16() using Zabha riscv: Implement arch_cmpxchg128() using Zacas riscv: Improve zacas fully-ordered cmpxchg() riscv: Implement cmpxchg8/16() using Zabha dt-bindings: riscv: Add Zabha ISA extension description riscv: Implement cmpxchg32/64() using Zacas riscv: Do not fail to build on byte/halfword operations with Zawrs riscv: Move cpufeature.h macros into their own header Link: https://lore.kernel.org/r/20241103145153.105097-1-alexghiti@rivosinc.com Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
2024-11-08Merge tag 'kvm-riscv-6.13-1' of https://github.com/kvm-riscv/linux into HEADPaolo Bonzini
KVM/riscv changes for 6.13 - Accelerate KVM RISC-V when running as a guest - Perf support to collect KVM guest statistics from host side
2024-11-05riscv: kvm: Fix out-of-bounds array accessBjörn Töpel
In kvm_riscv_vcpu_sbi_init() the entry->ext_idx can contain an out-of-bound index. This is used as a special marker for the base extensions, that cannot be disabled. However, when traversing the extensions, that special marker is not checked prior indexing the array. Add an out-of-bounds check to the function. Fixes: 56d8a385b605 ("RISC-V: KVM: Allow some SBI extensions to be disabled by default") Signed-off-by: Björn Töpel <bjorn@rivosinc.com> Reviewed-by: Anup Patel <anup@brainfault.org> Link: https://lore.kernel.org/r/20241104191503.74725-1-bjorn@kernel.org Signed-off-by: Anup Patel <anup@brainfault.org>
2024-11-05RISC-V: KVM: Fix APLIC in_clrip and clripnum write emulationYong-Xuan Wang
In the section "4.7 Precise effects on interrupt-pending bits" of the RISC-V AIA specification defines that: "If the source mode is Level1 or Level0 and the interrupt domain is configured in MSI delivery mode (domaincfg.DM = 1): The pending bit is cleared whenever the rectified input value is low, when the interrupt is forwarded by MSI, or by a relevant write to an in_clrip register or to clripnum." Update the aplic_write_pending() to match the spec. Fixes: d8dd9f113e16 ("RISC-V: KVM: Fix APLIC setipnum_le/be write emulation") Signed-off-by: Yong-Xuan Wang <yongxuan.wang@sifive.com> Reviewed-by: Vincent Chen <vincent.chen@sifive.com> Reviewed-by: Anup Patel <anup@brainfault.org> Link: https://lore.kernel.org/r/20241029085542.30541-1-yongxuan.wang@sifive.com Signed-off-by: Anup Patel <anup@brainfault.org>
2024-10-28RISC-V: KVM: Use NACL HFENCEs for KVM request based HFENCEsAnup Patel
When running under some other hypervisor, use SBI NACL based HFENCEs for TLB shoot-down via KVM requests. This makes HFENCEs faster whenever SBI nested acceleration is available. Signed-off-by: Anup Patel <apatel@ventanamicro.com> Reviewed-by: Atish Patra <atishp@rivosinc.com> Link: https://lore.kernel.org/r/20241020194734.58686-14-apatel@ventanamicro.com Signed-off-by: Anup Patel <anup@brainfault.org>
2024-10-28RISC-V: KVM: Save trap CSRs in kvm_riscv_vcpu_enter_exit()Anup Patel
Save trap CSRs in the kvm_riscv_vcpu_enter_exit() function instead of the kvm_arch_vcpu_ioctl_run() function so that HTVAL and HTINST CSRs are accessed in more optimized manner while running under some other hypervisor. Signed-off-by: Anup Patel <apatel@ventanamicro.com> Reviewed-by: Atish Patra <atishp@rivosinc.com> Link: https://lore.kernel.org/r/20241020194734.58686-13-apatel@ventanamicro.com Signed-off-by: Anup Patel <anup@brainfault.org>
2024-10-28RISC-V: KVM: Use SBI sync SRET call when availableAnup Patel
Implement an optimized KVM world-switch using SBI sync SRET call when SBI nested acceleration extension is available. This improves KVM world-switch when KVM RISC-V is running as a Guest under some other hypervisor. Signed-off-by: Anup Patel <apatel@ventanamicro.com> Reviewed-by: Atish Patra <atishp@rivosinc.com> Link: https://lore.kernel.org/r/20241020194734.58686-12-apatel@ventanamicro.com Signed-off-by: Anup Patel <anup@brainfault.org>
2024-10-28RISC-V: KVM: Use nacl_csr_xyz() for accessing AIA CSRsAnup Patel
When running under some other hypervisor, prefer nacl_csr_xyz() for accessing AIA CSRs in the run-loop. This makes CSR access faster whenever SBI nested acceleration is available. Signed-off-by: Anup Patel <apatel@ventanamicro.com> Reviewed-by: Atish Patra <atishp@rivosinc.com> Link: https://lore.kernel.org/r/20241020194734.58686-11-apatel@ventanamicro.com Signed-off-by: Anup Patel <anup@brainfault.org>
2024-10-28RISC-V: KVM: Use nacl_csr_xyz() for accessing H-extension CSRsAnup Patel
When running under some other hypervisor, prefer nacl_csr_xyz() for accessing H-extension CSRs in the run-loop. This makes CSR access faster whenever SBI nested acceleration is available. Signed-off-by: Anup Patel <apatel@ventanamicro.com> Reviewed-by: Atish Patra <atishp@rivosinc.com> Link: https://lore.kernel.org/r/20241020194734.58686-10-apatel@ventanamicro.com Signed-off-by: Anup Patel <anup@brainfault.org>
2024-10-28RISC-V: KVM: Add common nested acceleration supportAnup Patel
Add a common nested acceleration support which will be shared by all parts of KVM RISC-V. This nested acceleration support detects and enables SBI NACL extension usage based on static keys which ensures minimum impact on the non-nested scenario. Signed-off-by: Anup Patel <apatel@ventanamicro.com> Reviewed-by: Atish Patra <atishp@rivosinc.com> Link: https://lore.kernel.org/r/20241020194734.58686-9-apatel@ventanamicro.com Signed-off-by: Anup Patel <anup@brainfault.org>
2024-10-28RISC-V: KVM: Don't setup SGEI for zero guest external interruptsAnup Patel
No need to setup SGEI local interrupt when there are zero guest external interrupts (i.e. zero HW IMSIC guest files). Signed-off-by: Anup Patel <apatel@ventanamicro.com> Reviewed-by: Atish Patra <atishp@rivosinc.com> Link: https://lore.kernel.org/r/20241020194734.58686-7-apatel@ventanamicro.com Signed-off-by: Anup Patel <anup@brainfault.org>
2024-10-28RISC-V: KVM: Replace aia_set_hvictl() with aia_hvictl_value()Anup Patel
The aia_set_hvictl() internally writes the HVICTL CSR which makes it difficult to optimize the CSR write using SBI NACL extension for kvm_riscv_vcpu_aia_update_hvip() function so replace aia_set_hvictl() with new aia_hvictl_value() which only computes the HVICTL value. Signed-off-by: Anup Patel <apatel@ventanamicro.com> Reviewed-by: Atish Patra <atishp@rivosinc.com> Link: https://lore.kernel.org/r/20241020194734.58686-6-apatel@ventanamicro.com Signed-off-by: Anup Patel <anup@brainfault.org>
2024-10-28RISC-V: KVM: Break down the __kvm_riscv_switch_to() into macrosAnup Patel
Break down the __kvm_riscv_switch_to() function into macros so that these macros can be later re-used by SBI NACL extension based low-level switch function. Signed-off-by: Anup Patel <apatel@ventanamicro.com> Reviewed-by: Atish Patra <atishp@rivosinc.com> Link: https://lore.kernel.org/r/20241020194734.58686-5-apatel@ventanamicro.com Signed-off-by: Anup Patel <anup@brainfault.org>
2024-10-28RISC-V: KVM: Save/restore SCOUNTEREN in C sourceAnup Patel
The SCOUNTEREN CSR need not be saved/restored in the low-level __kvm_riscv_switch_to() function hence move the SCOUNTEREN CSR save/restore to the kvm_riscv_vcpu_swap_in_guest_state() and kvm_riscv_vcpu_swap_in_host_state() functions in C sources. Also, re-arrange the CSR save/restore and related GPR usage in the low-level __kvm_riscv_switch_to() low-level function. Signed-off-by: Anup Patel <apatel@ventanamicro.com> Reviewed-by: Atish Patra <atishp@rivosinc.com> Link: https://lore.kernel.org/r/20241020194734.58686-4-apatel@ventanamicro.com Signed-off-by: Anup Patel <anup@brainfault.org>
2024-10-28RISC-V: KVM: Save/restore HSTATUS in C sourceAnup Patel
We will be optimizing HSTATUS CSR access via shared memory setup using the SBI nested acceleration extension. To facilitate this, we first move HSTATUS save/restore in kvm_riscv_vcpu_enter_exit(). Signed-off-by: Anup Patel <apatel@ventanamicro.com> Reviewed-by: Atish Patra <atishp@rivosinc.com> Link: https://lore.kernel.org/r/20241020194734.58686-3-apatel@ventanamicro.com Signed-off-by: Anup Patel <anup@brainfault.org>
2024-10-28RISC-V: KVM: Order the object files alphabeticallyAnup Patel
Order the object files alphabetically in the Makefile so that it is very predictable inserting new object files in the future. Signed-off-by: Anup Patel <apatel@ventanamicro.com> Reviewed-by: Atish Patra <atishp@rivosinc.com> Link: https://lore.kernel.org/r/20241020194734.58686-2-apatel@ventanamicro.com Signed-off-by: Anup Patel <anup@brainfault.org>
2024-10-28riscv: KVM: add basic support for host vs guest profilingQuan Zhou
For the information collected on the host side, we need to identify which data originates from the guest and record these events separately, this can be achieved by having KVM register perf callbacks. Signed-off-by: Quan Zhou <zhouquan@iscas.ac.cn> Reviewed-by: Andrew Jones <ajones@ventanamicro.com> Link: https://lore.kernel.org/r/00342d535311eb0629b9ba4f1e457a48e2abee33.1728957131.git.zhouquan@iscas.ac.cn Signed-off-by: Anup Patel <anup@brainfault.org>
2024-10-25KVM: RISC-V: Use kvm_faultin_pfn() when mapping pfns into the guestSean Christopherson
Convert RISC-V to __kvm_faultin_pfn()+kvm_release_faultin_page(), which are new APIs to consolidate arch code and provide consistent behavior across all KVM architectures. Opportunisticaly fix a s/priort/prior typo in the related comment. Reviewed-by: Andrew Jones <ajones@ventanamicro.com> Acked-by: Anup Patel <anup@brainfault.org> Signed-off-by: Sean Christopherson <seanjc@google.com> Tested-by: Dmitry Osipenko <dmitry.osipenko@collabora.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> Message-ID: <20241010182427.1434605-60-seanjc@google.com>
2024-10-25KVM: RISC-V: Mark "struct page" pfns accessed before dropping mmu_lockSean Christopherson
Mark pages accessed before dropping mmu_lock when faulting in guest memory so that RISC-V can convert to kvm_release_faultin_page() without tripping its lockdep assertion on mmu_lock being held. Marking pages accessed outside of mmu_lock is ok (not great, but safe), but marking pages _dirty_ outside of mmu_lock can make filesystems unhappy (see the link below). Do both under mmu_lock to minimize the chances of doing the wrong thing in the future. Link: https://lore.kernel.org/all/cover.1683044162.git.lstoakes@gmail.com Reviewed-by: Andrew Jones <ajones@ventanamicro.com> Acked-by: Anup Patel <anup@brainfault.org> Signed-off-by: Sean Christopherson <seanjc@google.com> Tested-by: Dmitry Osipenko <dmitry.osipenko@collabora.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> Message-ID: <20241010182427.1434605-59-seanjc@google.com>
2024-10-25KVM: RISC-V: Mark "struct page" pfns dirty iff a stage-2 PTE is installedSean Christopherson
Don't mark pages dirty if KVM bails from the page fault handler without installing a stage-2 mapping, i.e. if the page is guaranteed to not be written by the guest. In addition to being a (very) minor fix, this paves the way for converting RISC-V to use kvm_release_faultin_page(). Reviewed-by: Andrew Jones <ajones@ventanamicro.com> Acked-by: Anup Patel <anup@brainfault.org> Signed-off-by: Sean Christopherson <seanjc@google.com> Tested-by: Dmitry Osipenko <dmitry.osipenko@collabora.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> Message-ID: <20241010182427.1434605-58-seanjc@google.com>
2024-10-24RISC-V: KVM: Allow Smnpm and Ssnpm extensions for guestsSamuel Holland
The interface for controlling pointer masking in VS-mode is henvcfg.PMM, which is part of the Ssnpm extension, even though pointer masking in HS-mode is provided by the Smnpm extension. As a result, emulating Smnpm in the guest requires (only) Ssnpm on the host. The guest configures Smnpm through the SBI Firmware Features extension, which KVM does not yet implement, so currently the ISA extension has no visible effect on the guest, and thus it cannot be disabled. Ssnpm is configured using the senvcfg CSR within the guest, so that extension cannot be hidden from the guest without intercepting writes to the CSR. Signed-off-by: Samuel Holland <samuel.holland@sifive.com> Reviewed-by: Anup Patel <anup@brainfault.org> Link: https://lore.kernel.org/r/20241016202814.4061541-10-samuel.holland@sifive.com Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
2024-10-20RISCV: KVM: use raw_spinlock for critical section in imsicCyan Yang
For the external interrupt updating procedure in imsic, there was a spinlock to protect it already. But since it should not be preempted in any cases, we should turn to use raw_spinlock to prevent any preemption in case PREEMPT_RT was enabled. Signed-off-by: Cyan Yang <cyan.yang@sifive.com> Reviewed-by: Yong-Xuan Wang <yongxuan.wang@sifive.com> Reviewed-by: Anup Patel <anup@brainfault.org> Message-ID: <20240919160126.44487-1-cyan.yang@sifive.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2024-09-17Merge branch 'kvm-redo-enable-virt' into HEADPaolo Bonzini
Register KVM's cpuhp and syscore callbacks when enabling virtualization in hardware, as the sole purpose of said callbacks is to disable and re-enable virtualization as needed. The primary motivation for this series is to simplify dealing with enabling virtualization for Intel's TDX, which needs to enable virtualization when kvm-intel.ko is loaded, i.e. long before the first VM is created. That said, this is a nice cleanup on its own. By registering the callbacks on-demand, the callbacks themselves don't need to check kvm_usage_count, because their very existence implies a non-zero count. Patch 1 (re)adds a dedicated lock for kvm_usage_count. This avoids a lock ordering issue between cpus_read_lock() and kvm_lock. The lock ordering issue still exist in very rare cases, and will be fixed for good by switching vm_list to an (S)RCU-protected list. Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2024-09-04KVM: Rename arch hooks related to per-CPU virtualization enablingSean Christopherson
Rename the per-CPU hooks used to enable virtualization in hardware to align with the KVM-wide helpers in kvm_main.c, and to better capture that the callbacks are invoked on every online CPU. No functional change intended. Suggested-by: Paolo Bonzini <pbonzini@redhat.com> Signed-off-by: Sean Christopherson <seanjc@google.com> Reviewed-by: Kai Huang <kai.huang@intel.com> Message-ID: <20240830043600.127750-5-seanjc@google.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2024-08-19RISC-V: KVM: Don't zero-out PMU snapshot area before freeing dataAnup Patel
With the latest Linux-6.11-rc3, the below NULL pointer crash is observed when SBI PMU snapshot is enabled for the guest and the guest is forcefully powered-off. Unable to handle kernel NULL pointer dereference at virtual address 0000000000000508 Oops [#1] Modules linked in: kvm CPU: 0 UID: 0 PID: 61 Comm: term-poll Not tainted 6.11.0-rc3-00018-g44d7178dd77a #3 Hardware name: riscv-virtio,qemu (DT) epc : __kvm_write_guest_page+0x94/0xa6 [kvm] ra : __kvm_write_guest_page+0x54/0xa6 [kvm] epc : ffffffff01590e98 ra : ffffffff01590e58 sp : ffff8f80001f39b0 gp : ffffffff81512a60 tp : ffffaf80024872c0 t0 : ffffaf800247e000 t1 : 00000000000007e0 t2 : 0000000000000000 s0 : ffff8f80001f39f0 s1 : 00007fff89ac4000 a0 : ffffffff015dd7e8 a1 : 0000000000000086 a2 : 0000000000000000 a3 : ffffaf8000000000 a4 : ffffaf80024882c0 a5 : 0000000000000000 a6 : ffffaf800328d780 a7 : 00000000000001cc s2 : ffffaf800197bd00 s3 : 00000000000828c4 s4 : ffffaf800248c000 s5 : ffffaf800247d000 s6 : 0000000000001000 s7 : 0000000000001000 s8 : 0000000000000000 s9 : 00007fff861fd500 s10: 0000000000000001 s11: 0000000000800000 t3 : 00000000000004d3 t4 : 00000000000004d3 t5 : ffffffff814126e0 t6 : ffffffff81412700 status: 0000000200000120 badaddr: 0000000000000508 cause: 000000000000000d [<ffffffff01590e98>] __kvm_write_guest_page+0x94/0xa6 [kvm] [<ffffffff015943a6>] kvm_vcpu_write_guest+0x56/0x90 [kvm] [<ffffffff015a175c>] kvm_pmu_clear_snapshot_area+0x42/0x7e [kvm] [<ffffffff015a1972>] kvm_riscv_vcpu_pmu_deinit.part.0+0xe0/0x14e [kvm] [<ffffffff015a2ad0>] kvm_riscv_vcpu_pmu_deinit+0x1a/0x24 [kvm] [<ffffffff0159b344>] kvm_arch_vcpu_destroy+0x28/0x4c [kvm] [<ffffffff0158e420>] kvm_destroy_vcpus+0x5a/0xda [kvm] [<ffffffff0159930c>] kvm_arch_destroy_vm+0x14/0x28 [kvm] [<ffffffff01593260>] kvm_destroy_vm+0x168/0x2a0 [kvm] [<ffffffff015933d4>] kvm_put_kvm+0x3c/0x58 [kvm] [<ffffffff01593412>] kvm_vm_release+0x22/0x2e [kvm] Clearly, the kvm_vcpu_write_guest() function is crashing because it is being called from kvm_pmu_clear_snapshot_area() upon guest tear down. To address the above issue, simplify the kvm_pmu_clear_snapshot_area() to not zero-out PMU snapshot area from kvm_pmu_clear_snapshot_area() because the guest is anyway being tore down. The kvm_pmu_clear_snapshot_area() is also called when guest changes PMU snapshot area of a VCPU but even in this case the previous PMU snaphsot area must not be zeroed-out because the guest might have reclaimed the pervious PMU snapshot area for some other purpose. Fixes: c2f41ddbcdd7 ("RISC-V: KVM: Implement SBI PMU Snapshot feature") Signed-off-by: Anup Patel <apatel@ventanamicro.com> Link: https://lore.kernel.org/r/20240815170907.2792229-1-apatel@ventanamicro.com Signed-off-by: Anup Patel <anup@brainfault.org>
2024-08-19RISC-V: KVM: Fix sbiret init before forwarding to userspaceAndrew Jones
When forwarding SBI calls to userspace ensure sbiret.error is initialized to SBI_ERR_NOT_SUPPORTED first, in case userspace neglects to set it to anything. If userspace neglects it then we can't be sure it did anything else either, so we just report it didn't do or try anything. Just init sbiret.value to zero, which is the preferred value to return when nothing special is specified. KVM was already initializing both sbiret.error and sbiret.value, but the values used appear to come from a copy+paste of the __sbi_ecall() implementation, i.e. a0 and a1, which don't apply prior to the call being executed, nor at all when forwarding to userspace. Fixes: dea8ee31a039 ("RISC-V: KVM: Add SBI v0.1 support") Signed-off-by: Andrew Jones <ajones@ventanamicro.com> Link: https://lore.kernel.org/r/20240807154943.150540-2-ajones@ventanamicro.com Signed-off-by: Anup Patel <anup@brainfault.org>
2024-07-20Merge tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvmLinus Torvalds
Pull kvm updates from Paolo Bonzini: "ARM: - Initial infrastructure for shadow stage-2 MMUs, as part of nested virtualization enablement - Support for userspace changes to the guest CTR_EL0 value, enabling (in part) migration of VMs between heterogenous hardware - Fixes + improvements to pKVM's FF-A proxy, adding support for v1.1 of the protocol - FPSIMD/SVE support for nested, including merged trap configuration and exception routing - New command-line parameter to control the WFx trap behavior under KVM - Introduce kCFI hardening in the EL2 hypervisor - Fixes + cleanups for handling presence/absence of FEAT_TCRX - Miscellaneous fixes + documentation updates LoongArch: - Add paravirt steal time support - Add support for KVM_DIRTY_LOG_INITIALLY_SET - Add perf kvm-stat support for loongarch RISC-V: - Redirect AMO load/store access fault traps to guest - perf kvm stat support - Use guest files for IMSIC virtualization, when available s390: - Assortment of tiny fixes which are not time critical x86: - Fixes for Xen emulation - Add a global struct to consolidate tracking of host values, e.g. EFER - Add KVM_CAP_X86_APIC_BUS_CYCLES_NS to allow configuring the effective APIC bus frequency, because TDX - Print the name of the APICv/AVIC inhibits in the relevant tracepoint - Clean up KVM's handling of vendor specific emulation to consistently act on "compatible with Intel/AMD", versus checking for a specific vendor - Drop MTRR virtualization, and instead always honor guest PAT on CPUs that support self-snoop - Update to the newfangled Intel CPU FMS infrastructure - Don't advertise IA32_PERF_GLOBAL_OVF_CTRL as an MSR-to-be-saved, as it reads '0' and writes from userspace are ignored - Misc cleanups x86 - MMU: - Small cleanups, renames and refactoring extracted from the upcoming Intel TDX support - Don't allocate kvm_mmu_page.shadowed_translation for shadow pages that can't hold leafs SPTEs - Unconditionally drop mmu_lock when allocating TDP MMU page tables for eager page splitting, to avoid stalling vCPUs when splitting huge pages - Bug the VM instead of simply warning if KVM tries to split a SPTE that is non-present or not-huge. KVM is guaranteed to end up in a broken state because the callers fully expect a valid SPTE, it's all but dangerous to let more MMU changes happen afterwards x86 - AMD: - Make per-CPU save_area allocations NUMA-aware - Force sev_es_host_save_area() to be inlined to avoid calling into an instrumentable function from noinstr code - Base support for running SEV-SNP guests. API-wise, this includes a new KVM_X86_SNP_VM type, encrypting/measure the initial image into guest memory, and finalizing it before launching it. Internally, there are some gmem/mmu hooks needed to prepare gmem-allocated pages before mapping them into guest private memory ranges This includes basic support for attestation guest requests, enough to say that KVM supports the GHCB 2.0 specification There is no support yet for loading into the firmware those signing keys to be used for attestation requests, and therefore no need yet for the host to provide certificate data for those keys. To support fetching certificate data from userspace, a new KVM exit type will be needed to handle fetching the certificate from userspace. An attempt to define a new KVM_EXIT_COCO / KVM_EXIT_COCO_REQ_CERTS exit type to handle this was introduced in v1 of this patchset, but is still being discussed by community, so for now this patchset only implements a stub version of SNP Extended Guest Requests that does not provide certificate data x86 - Intel: - Remove an unnecessary EPT TLB flush when enabling hardware - Fix a series of bugs that cause KVM to fail to detect nested pending posted interrupts as valid wake eents for a vCPU executing HLT in L2 (with HLT-exiting disable by L1) - KVM: x86: Suppress MMIO that is triggered during task switch emulation Explicitly suppress userspace emulated MMIO exits that are triggered when emulating a task switch as KVM doesn't support userspace MMIO during complex (multi-step) emulation Silently ignoring the exit request can result in the WARN_ON_ONCE(vcpu->mmio_needed) firing if KVM exits to userspace for some other reason prior to purging mmio_needed See commit 0dc902267cb3 ("KVM: x86: Suppress pending MMIO write exits if emulator detects exception") for more details on KVM's limitations with respect to emulated MMIO during complex emulator flows Generic: - Rename the AS_UNMOVABLE flag that was introduced for KVM to AS_INACCESSIBLE, because the special casing needed by these pages is not due to just unmovability (and in fact they are only unmovable because the CPU cannot access them) - New ioctl to populate the KVM page tables in advance, which is useful to mitigate KVM page faults during guest boot or after live migration. The code will also be used by TDX, but (probably) not through the ioctl - Enable halt poll shrinking by default, as Intel found it to be a clear win - Setup empty IRQ routing when creating a VM to avoid having to synchronize SRCU when creating a split IRQCHIP on x86 - Rework the sched_in/out() paths to replace kvm_arch_sched_in() with a flag that arch code can use for hooking both sched_in() and sched_out() - Take the vCPU @id as an "unsigned long" instead of "u32" to avoid truncating a bogus value from userspace, e.g. to help userspace detect bugs - Mark a vCPU as preempted if and only if it's scheduled out while in the KVM_RUN loop, e.g. to avoid marking it preempted and thus writing guest memory when retrieving guest state during live migration blackout Selftests: - Remove dead code in the memslot modification stress test - Treat "branch instructions retired" as supported on all AMD Family 17h+ CPUs - Print the guest pseudo-RNG seed only when it changes, to avoid spamming the log for tests that create lots of VMs - Make the PMU counters test less flaky when counting LLC cache misses by doing CLFLUSH{OPT} in every loop iteration" * tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm: (227 commits) crypto: ccp: Add the SNP_VLEK_LOAD command KVM: x86/pmu: Add kvm_pmu_call() to simplify static calls of kvm_pmu_ops KVM: x86: Introduce kvm_x86_call() to simplify static calls of kvm_x86_ops KVM: x86: Replace static_call_cond() with static_call() KVM: SEV: Provide support for SNP_EXTENDED_GUEST_REQUEST NAE event x86/sev: Move sev_guest.h into common SEV header KVM: SEV: Provide support for SNP_GUEST_REQUEST NAE event KVM: x86: Suppress MMIO that is triggered during task switch emulation KVM: x86/mmu: Clean up make_huge_page_split_spte() definition and intro KVM: x86/mmu: Bug the VM if KVM tries to split a !hugepage SPTE KVM: selftests: x86: Add test for KVM_PRE_FAULT_MEMORY KVM: x86: Implement kvm_arch_vcpu_pre_fault_memory() KVM: x86/mmu: Make kvm_mmu_do_page_fault() return mapped level KVM: x86/mmu: Account pf_{fixed,emulate,spurious} in callers of "do page fault" KVM: x86/mmu: Bump pf_taken stat only in the "real" page fault handler KVM: Add KVM_PRE_FAULT_MEMORY vcpu ioctl to pre-populate guest memory KVM: Document KVM_PRE_FAULT_MEMORY ioctl mm, virt: merge AS_UNMOVABLE and AS_INACCESSIBLE perf kvm: Add kvm-stat for loongarch64 LoongArch: KVM: Add PV steal time support in guest side ...
2024-07-20Merge tag 'riscv-for-linus-6.11-mw1' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/riscv/linux Pull RISC-V updates from Palmer Dabbelt: - Support for various new ISA extensions: * The Zve32[xf] and Zve64[xfd] sub-extensios of the vector extension * Zimop and Zcmop for may-be-operations * The Zca, Zcf, Zcd and Zcb sub-extensions of the C extension * Zawrs - riscv,cpu-intc is now dtschema - A handful of performance improvements and cleanups to text patching - Support for memory hot{,un}plug - The highest user-allocatable virtual address is now visible in hwprobe * tag 'riscv-for-linus-6.11-mw1' of git://git.kernel.org/pub/scm/linux/kernel/git/riscv/linux: (58 commits) riscv: lib: relax assembly constraints in hweight riscv: set trap vector earlier KVM: riscv: selftests: Add Zawrs extension to get-reg-list test KVM: riscv: Support guest wrs.nto riscv: hwprobe: export Zawrs ISA extension riscv: Add Zawrs support for spinlocks dt-bindings: riscv: Add Zawrs ISA extension description riscv: Provide a definition for 'pause' riscv: hwprobe: export highest virtual userspace address riscv: Improve sbi_ecall() code generation by reordering arguments riscv: Add tracepoints for SBI calls and returns riscv: Optimize crc32 with Zbc extension riscv: Enable DAX VMEMMAP optimization riscv: mm: Add support for ZONE_DEVICE virtio-mem: Enable virtio-mem for RISC-V riscv: Enable memory hotplugging for RISC-V riscv: mm: Take memory hotplug read-lock during kernel page table dump riscv: mm: Add memory hotplugging support riscv: mm: Add pfn_to_kaddr() implementation riscv: mm: Refactor create_linear_mapping_range() for memory hot add ...
2024-07-16Merge tag 'kvm-x86-generic-6.11' of https://github.com/kvm-x86/linux into HEADPaolo Bonzini
KVM generic changes for 6.11 - Enable halt poll shrinking by default, as Intel found it to be a clear win. - Setup empty IRQ routing when creating a VM to avoid having to synchronize SRCU when creating a split IRQCHIP on x86. - Rework the sched_in/out() paths to replace kvm_arch_sched_in() with a flag that arch code can use for hooking both sched_in() and sched_out(). - Take the vCPU @id as an "unsigned long" instead of "u32" to avoid truncating a bogus value from userspace, e.g. to help userspace detect bugs. - Mark a vCPU as preempted if and only if it's scheduled out while in the KVM_RUN loop, e.g. to avoid marking it preempted and thus writing guest memory when retrieving guest state during live migration blackout. - A few minor cleanups
2024-07-12Merge patch series "riscv: Apply Zawrs when available"Palmer Dabbelt
Andrew Jones <ajones@ventanamicro.com> says: Zawrs provides two instructions (wrs.nto and wrs.sto), where both are meant to allow the hart to enter a low-power state while waiting on a store to a memory location. The instructions also both wait an implementation-defined "short" duration (unless the implementation terminates the stall for another reason). The difference is that while wrs.sto will terminate when the duration elapses, wrs.nto, depending on configuration, will either just keep waiting or an ILL exception will be raised. Linux will use wrs.nto, so if platforms have an implementation which falls in the "just keep waiting" category (which is not expected), then it should _not_ advertise Zawrs in the hardware description. Like wfi (and with the same {m,h}status bits to configure it), when wrs.nto is configured to raise exceptions it's expected that the higher privilege level will see the instruction was a wait instruction, do something, and then resume execution following the instruction. For example, KVM does configure exceptions for wfi (hstatus.VTW=1) and therefore also for wrs.nto. KVM does this for wfi since it's better to allow other tasks to be scheduled while a VCPU waits for an interrupt. For waits such as those where wrs.nto/sto would be used, which are typically locks, it is also a good idea for KVM to be involved, as it can attempt to schedule the lock holding VCPU. This series starts with Christoph's addition of the riscv smp_cond_load_relaxed function which applies wrs.sto when available. That patch has been reworked to use wrs.nto and to use the same approach as Arm for the wait loop, since we can't have arbitrary C code between the load-reserved and the wrs. Then, hwprobe support is added (since the instructions are also usable from usermode), and finally KVM is taught about wrs.nto, allowing guests to see and use the Zawrs extension. We still don't have test results from hardware, and it's not possible to prove that using Zawrs is a win when testing on QEMU, not even when oversubscribing VCPUs to guests. However, it is possible to use KVM selftests to force a scenario where we can prove Zawrs does its job and does it well. [4] is a test which does this and, on my machine, without Zawrs it takes 16 seconds to complete and with Zawrs it takes 0.25 seconds. This series is also available here [1]. In order to use QEMU for testing a build with [2] is needed. In order to enable guests to use Zawrs with KVM using kvmtool, the branch at [3] may be used. [1] https://github.com/jones-drew/linux/commits/riscv/zawrs-v3/ [2] https://lore.kernel.org/all/20240312152901.512001-2-ajones@ventanamicro.com/ [3] https://github.com/jones-drew/kvmtool/commits/riscv/zawrs/ [4] https://github.com/jones-drew/linux/commit/cb2beccebcece10881db842ed69bdd5715cfab5d Link: https://lore.kernel.org/r/20240426100820.14762-8-ajones@ventanamicro.com * b4-shazam-merge: KVM: riscv: selftests: Add Zawrs extension to get-reg-list test KVM: riscv: Support guest wrs.nto riscv: hwprobe: export Zawrs ISA extension riscv: Add Zawrs support for spinlocks dt-bindings: riscv: Add Zawrs ISA extension description riscv: Provide a definition for 'pause' Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
2024-07-12KVM: riscv: Support guest wrs.ntoAndrew Jones
When a guest traps on wrs.nto, call kvm_vcpu_on_spin() to attempt to yield to the lock holding VCPU. Also extend the KVM ISA extension ONE_REG interface to allow KVM userspace to detect and enable the Zawrs extension for the Guest/VM. Signed-off-by: Andrew Jones <ajones@ventanamicro.com> Acked-by: Anup Patel <anup@brainfault.org> Link: https://lore.kernel.org/r/20240426100820.14762-13-ajones@ventanamicro.com Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
2024-07-12Merge tag 'loongarch-kvm-6.11' of ↵Paolo Bonzini
git://git.kernel.org/pub/scm/linux/kernel/git/chenhuacai/linux-loongson into HEAD LoongArch KVM changes for v6.11 1. Add ParaVirt steal time support. 2. Add some VM migration enhancement. 3. Add perf kvm-stat support for loongarch.
2024-07-03Merge patch series "Assorted fixes in RISC-V PMU driver"Palmer Dabbelt
Atish Patra <atishp@rivosinc.com> says: This series contains 3 fixes out of which the first one is a new fix for invalid event data reported in lkml[2]. The last two are v3 of Samuel's patch[1]. I added the RB/TB/Fixes tag and moved 1 unrelated change to its own patch. I also changed an error message in kvm vcpu_pmu from pr_err to pr_debug to avoid redundant failure error messages generated due to the boot time quering of events implemented in the patch[1] Here is the original cover letter for the patch[1] Before this patch: $ perf list hw List of pre-defined events (to be used in -e or -M): branch-instructions OR branches [Hardware event] branch-misses [Hardware event] bus-cycles [Hardware event] cache-misses [Hardware event] cache-references [Hardware event] cpu-cycles OR cycles [Hardware event] instructions [Hardware event] ref-cycles [Hardware event] stalled-cycles-backend OR idle-cycles-backend [Hardware event] stalled-cycles-frontend OR idle-cycles-frontend [Hardware event] $ perf stat -ddd true Performance counter stats for 'true': 4.36 msec task-clock # 0.744 CPUs utilized 1 context-switches # 229.325 /sec 0 cpu-migrations # 0.000 /sec 38 page-faults # 8.714 K/sec 4,375,694 cycles # 1.003 GHz (60.64%) 728,945 instructions # 0.17 insn per cycle 79,199 branches # 18.162 M/sec 17,709 branch-misses # 22.36% of all branches 181,734 L1-dcache-loads # 41.676 M/sec 5,547 L1-dcache-load-misses # 3.05% of all L1-dcache accesses <not counted> LLC-loads (0.00%) <not counted> LLC-load-misses (0.00%) <not counted> L1-icache-loads (0.00%) <not counted> L1-icache-load-misses (0.00%) <not counted> dTLB-loads (0.00%) <not counted> dTLB-load-misses (0.00%) <not counted> iTLB-loads (0.00%) <not counted> iTLB-load-misses (0.00%) <not counted> L1-dcache-prefetches (0.00%) <not counted> L1-dcache-prefetch-misses (0.00%) 0.005860375 seconds time elapsed 0.000000000 seconds user 0.010383000 seconds sys After this patch: $ perf list hw List of pre-defined events (to be used in -e or -M): branch-instructions OR branches [Hardware event] branch-misses [Hardware event] cache-misses [Hardware event] cache-references [Hardware event] cpu-cycles OR cycles [Hardware event] instructions [Hardware event] $ perf stat -ddd true Performance counter stats for 'true': 5.16 msec task-clock # 0.848 CPUs utilized 1 context-switches # 193.817 /sec 0 cpu-migrations # 0.000 /sec 37 page-faults # 7.171 K/sec 5,183,625 cycles # 1.005 GHz 961,696 instructions # 0.19 insn per cycle 85,853 branches # 16.640 M/sec 20,462 branch-misses # 23.83% of all branches 243,545 L1-dcache-loads # 47.203 M/sec 5,974 L1-dcache-load-misses # 2.45% of all L1-dcache accesses <not supported> LLC-loads <not supported> LLC-load-misses <not supported> L1-icache-loads <not supported> L1-icache-load-misses <not supported> dTLB-loads 19,619 dTLB-load-misses <not supported> iTLB-loads 6,831 iTLB-load-misses <not supported> L1-dcache-prefetches <not supported> L1-dcache-prefetch-misses 0.006085625 seconds time elapsed 0.000000000 seconds user 0.013022000 seconds sys [1] https://lore.kernel.org/linux-riscv/20240418014652.1143466-1-samuel.holland@sifive.com/ [2] https://lore.kernel.org/all/CC51D53B-846C-4D81-86FC-FBF969D0A0D6@pku.edu.cn/ * b4-shazam-merge: perf: RISC-V: Check standard event availability drivers/perf: riscv: Reset the counter to hpmevent mapping while starting cpus drivers/perf: riscv: Do not update the event data if uptodate Link: https://lore.kernel.org/r/20240628-misc_perf_fixes-v4-0-e01cfddcf035@rivosinc.com Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>