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2022-09-26KVM: nVMX: Use CC() macro to handle eVMCS unsupported controls checksSean Christopherson
Locally #define and use the nested virtualization Consistency Check (CC) macro to handle eVMCS unsupported controls checks. Using the macro loses the existing printing of the unsupported controls, but that's a feature and not a bug. The existing approach is flawed because the @err param to trace_kvm_nested_vmenter_failed() is the error code, not the error value. The eVMCS trickery mostly works as __print_symbolic() falls back to printing the raw hex value, but that subtly relies on not having a match between the unsupported value and VMX_VMENTER_INSTRUCTION_ERRORS. If it's really truly necessary to snapshot the bad value, then the tracepoint can be extended in the future. Signed-off-by: Sean Christopherson <seanjc@google.com> Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com> Signed-off-by: Sean Christopherson <seanjc@google.com> Link: https://lore.kernel.org/r/20220830133737.1539624-9-vkuznets@redhat.com Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2022-09-26KVM: nVMX: Refactor unsupported eVMCS controls logic to use 2-d arrayVitaly Kuznetsov
Refactor the handling of unsupported eVMCS to use a 2-d array to store the set of unsupported controls. KVM's handling of eVMCS is completely broken as there is no way for userspace to query which features are unsupported, nor does KVM prevent userspace from attempting to enable unsupported features. A future commit will remedy that by filtering and enforcing unsupported features when eVMCS, but that needs to be opt-in from userspace to avoid breakage, i.e. KVM needs to maintain its legacy behavior by snapshotting the exact set of controls that are currently (un)supported by eVMCS. No functional change intended. Suggested-by: Paolo Bonzini <pbonzini@redhat.com> Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com> [sean: split to standalone patch, write changelog] Signed-off-by: Sean Christopherson <seanjc@google.com> Link: https://lore.kernel.org/r/20220830133737.1539624-8-vkuznets@redhat.com Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2022-09-26KVM: nVMX: Treat eVMCS as enabled for guest iff Hyper-V is also enabledSean Christopherson
When querying whether or not eVMCS is enabled on behalf of the guest, treat eVMCS as enable if and only if Hyper-V is enabled/exposed to the guest. Note, flows that come from the host, e.g. KVM_SET_NESTED_STATE, must NOT check for Hyper-V being enabled as KVM doesn't require guest CPUID to be set before most ioctls(). Signed-off-by: Sean Christopherson <seanjc@google.com> Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com> Signed-off-by: Sean Christopherson <seanjc@google.com> Link: https://lore.kernel.org/r/20220830133737.1539624-7-vkuznets@redhat.com Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2022-09-26KVM: x86: Report error when setting CPUID if Hyper-V allocation failsSean Christopherson
Return -ENOMEM back to userspace if allocating the Hyper-V vCPU struct fails when enabling Hyper-V in guest CPUID. Silently ignoring failure means that KVM will not have an up-to-date CPUID cache if allocating the struct succeeds later on, e.g. when activating SynIC. Rejecting the CPUID operation also guarantess that vcpu->arch.hyperv is non-NULL if hyperv_enabled is true, which will allow for additional cleanup, e.g. in the eVMCS code. Note, the initialization needs to be done before CPUID is set, and more subtly before kvm_check_cpuid(), which potentially enables dynamic XFEATURES. Sadly, there's no easy way to avoid exposing Hyper-V details to CPUID or vice versa. Expose kvm_hv_vcpu_init() and the Hyper-V CPUID signature to CPUID instead of exposing cpuid_entry2_find() outside of CPUID code. It's hard to envision kvm_hv_vcpu_init() being misused, whereas cpuid_entry2_find() absolutely shouldn't be used outside of core CPUID code. Fixes: 10d7bf1e46dc ("KVM: x86: hyper-v: Cache guest CPUID leaves determining features availability") Signed-off-by: Sean Christopherson <seanjc@google.com> Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com> Signed-off-by: Sean Christopherson <seanjc@google.com> Link: https://lore.kernel.org/r/20220830133737.1539624-6-vkuznets@redhat.com Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2022-09-26KVM: x86: Check for existing Hyper-V vCPU in kvm_hv_vcpu_init()Sean Christopherson
When potentially allocating/initializing the Hyper-V vCPU struct, check for an existing instance in kvm_hv_vcpu_init() instead of requiring callers to perform the check. Relying on callers to do the check is risky as it's all too easy for KVM to overwrite vcpu->arch.hyperv and leak memory, and it adds additional burden on callers without much benefit. No functional change intended. Signed-off-by: Sean Christopherson <seanjc@google.com> Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com> Signed-off-by: Sean Christopherson <seanjc@google.com> Reviewed-by: Wei Liu <wei.liu@kernel.org> Link: https://lore.kernel.org/r/20220830133737.1539624-5-vkuznets@redhat.com Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2022-09-26KVM: x86: Zero out entire Hyper-V CPUID cache before processing entriesVitaly Kuznetsov
Wipe the whole 'hv_vcpu->cpuid_cache' with memset() instead of having to zero each particular member when the corresponding CPUID entry was not found. No functional change intended. Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com> [sean: split to separate patch] Signed-off-by: Sean Christopherson <seanjc@google.com> Reviewed-by: Wei Liu <wei.liu@kernel.org> Link: https://lore.kernel.org/r/20220830133737.1539624-4-vkuznets@redhat.com Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2022-09-26KVM: VMX: Do not declare vmread_error() asmlinkageUros Bizjak
There is no need to declare vmread_error() asmlinkage, its arguments can be passed via registers for both 32-bit and 64-bit targets. Function argument registers are considered call-clobbered registers, they are saved in the trampoline just before the function call and restored afterwards. Dropping "asmlinkage" patch unifies trampoline function argument handling between 32-bit and 64-bit targets and improves generated code for 32-bit targets. Cc: Paolo Bonzini <pbonzini@redhat.com> Cc: Sean Christopherson <seanjc@google.com> Signed-off-by: Uros Bizjak <ubizjak@gmail.com> Link: https://lore.kernel.org/r/20220817144045.3206-1-ubizjak@gmail.com Signed-off-by: Sean Christopherson <seanjc@google.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2022-09-26KVM:x86: Clean up ModR/M "reg" initialization in reg op decodingLiam Ni
Refactor decode_register_operand() to get the ModR/M register if and only if the instruction uses a ModR/M encoding to make it more obvious how the register operand is retrieved. Signed-off-by: Liam Ni <zhiguangni01@gmail.com> Link: https://lore.kernel.org/r/20220908141210.1375828-1-zhiguangni01@zhaoxin.com Signed-off-by: Sean Christopherson <seanjc@google.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2022-09-26KVM: x86: Print guest pgd in kvm_nested_vmenter()Mingwei Zhang
Print guest pgd in kvm_nested_vmenter() to enrich the information for tracing. When tdp is enabled, print the value of tdp page table (EPT/NPT); when tdp is disabled, print the value of non-nested CR3. Suggested-by: Sean Christopherson <seanjc@google.com> Signed-off-by: Mingwei Zhang <mizhang@google.com> Link: https://lore.kernel.org/r/20220825225755.907001-4-mizhang@google.com [sean: print nested_cr3 vs. nested_eptp vs. guest_cr3] Signed-off-by: Sean Christopherson <seanjc@google.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2022-09-26KVM: nVMX: Add tracepoint for nested VM-EnterDavid Matlack
Call trace_kvm_nested_vmenter() during nested VMLAUNCH/VMRESUME to bring parity with nSVM's usage of the tracepoint during nested VMRUN. Attempt to use analagous VMCS fields to the VMCB fields that are reported in the SVM case: "int_ctl": 32-bit field of the VMCB that the CPU uses to deliver virtual interrupts. The analagous VMCS field is the 16-bit "guest interrupt status". "event_inj": 32-bit field of VMCB that is used to inject events (exceptions and interrupts) into the guest. The analagous VMCS field is the "VM-entry interruption-information field". "npt_enabled": 1 when the VCPU has enabled nested paging. The analagous VMCS field is the enable-EPT execution control. "npt_addr": 64-bit field when the VCPU has enabled nested paging. The analagous VMCS field is the ept_pointer. Signed-off-by: David Matlack <dmatlack@google.com> [move the code into the nested_vmx_enter_non_root_mode().] Signed-off-by: Mingwei Zhang <mizhang@google.com> Link: https://lore.kernel.org/r/20220825225755.907001-3-mizhang@google.com Signed-off-by: Sean Christopherson <seanjc@google.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2022-09-26KVM: x86: Update trace function for nested VM entry to support VMXMingwei Zhang
Update trace function for nested VM entry to support VMX. Existing trace function only supports nested VMX and the information printed out is AMD specific. So, rename trace_kvm_nested_vmrun() to trace_kvm_nested_vmenter(), since 'vmenter' is generic. Add a new field 'isa' to recognize Intel and AMD; Update the output to print out VMX/SVM related naming respectively, eg., vmcb vs. vmcs; npt vs. ept. Opportunistically update the call site of trace_kvm_nested_vmenter() to make one line per parameter. Signed-off-by: Mingwei Zhang <mizhang@google.com> Link: https://lore.kernel.org/r/20220825225755.907001-2-mizhang@google.com [sean: align indentation, s/update/rename in changelog] Signed-off-by: Sean Christopherson <seanjc@google.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2022-09-26KVM: x86: Use u64 for address and error code in page fault tracepointSean Christopherson
Track the address and error code as 64-bit values in the page fault tracepoint. When TDP is enabled, the address is a GPA and thus can be a 64-bit value even on 32-bit hosts. And SVM's #NPF genereates 64-bit error codes. Opportunistically clean up the formatting. Signed-off-by: Sean Christopherson <seanjc@google.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2022-09-26KVM: Add extra information in kvm_page_fault trace pointWonhyuk Yang
Currently, kvm_page_fault trace point provide fault_address and error code. However it is not enough to find which cpu and instruction cause kvm_page_faults. So add vcpu id and instruction pointer in kvm_page_fault trace point. Cc: Baik Song An <bsahn@etri.re.kr> Cc: Hong Yeon Kim <kimhy@etri.re.kr> Cc: Taeung Song <taeung@reallinux.co.kr> Cc: linuxgeek@linuxgeek.io Signed-off-by: Wonhyuk Yang <vvghjk1234@gmail.com> Link: https://lore.kernel.org/r/20220510071001.87169-1-vvghjk1234@gmail.com Signed-off-by: Sean Christopherson <seanjc@google.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2022-09-26KVM: SVM: remove unnecessary check on INIT interceptPaolo Bonzini
Since svm_check_nested_events() is now handling INIT signals, there is no need to latch it until the VMEXIT is injected. The only condition under which INIT signals are latched is GIF=0. Suggested-by: Maxim Levitsky <mlevitsk@redhat.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> Reviewed-by: Maxim Levitsky <mlevitsk@redhat.com> Link: https://lore.kernel.org/r/20220819165643.83692-1-pbonzini@redhat.com Signed-off-by: Sean Christopherson <seanjc@google.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2022-09-26KVM/VMX: Avoid stack engine synchronization uop in __vmx_vcpu_runUros Bizjak
Avoid instructions with explicit uses of the stack pointer between instructions that implicitly refer to it. The sequence of POP %reg; ADD $x, %RSP; POP %reg forces emission of synchronization uop to synchronize the value of the stack pointer in the stack engine and the out-of-order core. Using POP with the dummy register instead of ADD $x, %RSP results in a smaller code size and faster code. The patch also fixes the reference to the wrong register in the nearby comment. Cc: Paolo Bonzini <pbonzini@redhat.com> Cc: Sean Christopherson <seanjc@google.com> Signed-off-by: Uros Bizjak <ubizjak@gmail.com> Link: https://lore.kernel.org/r/20220816211010.25693-1-ubizjak@gmail.com Signed-off-by: Sean Christopherson <seanjc@google.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2022-09-22KVM: x86: Inject #UD on emulated XSETBV if XSAVES isn't enabledSean Christopherson
Inject #UD when emulating XSETBV if CR4.OSXSAVE is not set. This also covers the "XSAVE not supported" check, as setting CR4.OSXSAVE=1 #GPs if XSAVE is not supported (and userspace gets to keep the pieces if it forces incoherent vCPU state). Add a comment to kvm_emulate_xsetbv() to call out that the CPU checks CR4.OSXSAVE before checking for intercepts. AMD'S APM implies that #UD has priority (says that intercepts are checked before #GP exceptions), while Intel's SDM says nothing about interception priority. However, testing on hardware shows that both AMD and Intel CPUs prioritize the #UD over interception. Fixes: 02d4160fbd76 ("x86: KVM: add xsetbv to the emulator") Cc: stable@vger.kernel.org Cc: Vitaly Kuznetsov <vkuznets@redhat.com> Signed-off-by: Sean Christopherson <seanjc@google.com> Message-Id: <20220824033057.3576315-4-seanjc@google.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2022-09-22KVM: x86: Always enable legacy FP/SSE in allowed user XFEATURESDr. David Alan Gilbert
Allow FP and SSE state to be saved and restored via KVM_{G,SET}_XSAVE on XSAVE-capable hosts even if their bits are not exposed to the guest via XCR0. Failing to allow FP+SSE first showed up as a QEMU live migration failure, where migrating a VM from a pre-XSAVE host, e.g. Nehalem, to an XSAVE host failed due to KVM rejecting KVM_SET_XSAVE. However, the bug also causes problems even when migrating between XSAVE-capable hosts as KVM_GET_SAVE won't set any bits in user_xfeatures if XSAVE isn't exposed to the guest, i.e. KVM will fail to actually migrate FP+SSE. Because KVM_{G,S}ET_XSAVE are designed to allowing migrating between hosts with and without XSAVE, KVM_GET_XSAVE on a non-XSAVE (by way of fpu_copy_guest_fpstate_to_uabi()) always sets the FP+SSE bits in the header so that KVM_SET_XSAVE will work even if the new host supports XSAVE. Fixes: ad856280ddea ("x86/kvm/fpu: Limit guest user_xfeatures to supported bits of XCR0") bz: https://bugzilla.redhat.com/show_bug.cgi?id=2079311 Cc: stable@vger.kernel.org Cc: Leonardo Bras <leobras@redhat.com> Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com> [sean: add comment, massage changelog] Signed-off-by: Sean Christopherson <seanjc@google.com> Message-Id: <20220824033057.3576315-3-seanjc@google.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2022-09-22KVM: x86: Reinstate kvm_vcpu_arch.guest_supported_xcr0Sean Christopherson
Reinstate the per-vCPU guest_supported_xcr0 by partially reverting commit 988896bb6182; the implicit assessment that guest_supported_xcr0 is always the same as guest_fpu.fpstate->user_xfeatures was incorrect. kvm_vcpu_after_set_cpuid() isn't the only place that sets user_xfeatures, as user_xfeatures is set to fpu_user_cfg.default_features when guest_fpu is allocated via fpu_alloc_guest_fpstate() => __fpstate_reset(). guest_supported_xcr0 on the other hand is zero-allocated. If userspace never invokes KVM_SET_CPUID2, supported XCR0 will be '0', whereas the allowed user XFEATURES will be non-zero. Practically speaking, the edge case likely doesn't matter as no sane userspace will live migrate a VM without ever doing KVM_SET_CPUID2. The primary motivation is to prepare for KVM intentionally and explicitly setting bits in user_xfeatures that are not set in guest_supported_xcr0. Because KVM_{G,S}ET_XSAVE can be used to svae/restore FP+SSE state even if the host doesn't support XSAVE, KVM needs to set the FP+SSE bits in user_xfeatures even if they're not allowed in XCR0, e.g. because XCR0 isn't exposed to the guest. At that point, the simplest fix is to track the two things separately (allowed save/restore vs. allowed XCR0). Fixes: 988896bb6182 ("x86/kvm/fpu: Remove kvm_vcpu_arch.guest_supported_xcr0") Cc: stable@vger.kernel.org Cc: Leonardo Bras <leobras@redhat.com> Signed-off-by: Sean Christopherson <seanjc@google.com> Message-Id: <20220824033057.3576315-2-seanjc@google.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2022-09-22KVM: x86/mmu: add missing update to max_mmu_rmap_sizeMiaohe Lin
The update to statistic max_mmu_rmap_size is unintentionally removed by commit 4293ddb788c1 ("KVM: x86/mmu: Remove redundant spte present check in mmu_set_spte"). Add missing update to it or max_mmu_rmap_size will always be nonsensical 0. Fixes: 4293ddb788c1 ("KVM: x86/mmu: Remove redundant spte present check in mmu_set_spte") Signed-off-by: Miaohe Lin <linmiaohe@huawei.com> Message-Id: <20220907080657.42898-1-linmiaohe@huawei.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2022-09-01Merge tag 'kvm-s390-master-6.0-1' of ↵Paolo Bonzini
git://git.kernel.org/pub/scm/linux/kernel/git/kvms390/linux into HEAD PCI interpretation compile fixes
2022-09-01KVM: x86: check validity of argument to KVM_SET_MP_STATEPaolo Bonzini
An invalid argument to KVM_SET_MP_STATE has no effect other than making the vCPU fail to run at the next KVM_RUN. Since it is extremely unlikely that any userspace is relying on it, fail with -EINVAL just like for other architectures. Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2022-09-01KVM: x86: fix memoryleak in kvm_arch_vcpu_create()Miaohe Lin
When allocating memory for mci_ctl2_banks fails, KVM doesn't release mce_banks leading to memoryleak. Fix this issue by calling kfree() for it when kcalloc() fails. Fixes: 281b52780b57 ("KVM: x86: Add emulation for MSR_IA32_MCx_CTL2 MSRs.") Signed-off-by: Miaohe Lin <linmiaohe@huawei.com> Message-Id: <20220901122300.22298-1-linmiaohe@huawei.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2022-09-01KVM: x86: Mask off unsupported and unknown bits of IA32_ARCH_CAPABILITIESJim Mattson
KVM should not claim to virtualize unknown IA32_ARCH_CAPABILITIES bits. When kvm_get_arch_capabilities() was originally written, there were only a few bits defined in this MSR, and KVM could virtualize all of them. However, over the years, several bits have been defined that KVM cannot just blindly pass through to the guest without additional work (such as virtualizing an MSR promised by the IA32_ARCH_CAPABILITES feature bit). Define a mask of supported IA32_ARCH_CAPABILITIES bits, and mask off any other bits that are set in the hardware MSR. Cc: Paolo Bonzini <pbonzini@redhat.com> Fixes: 5b76a3cff011 ("KVM: VMX: Tell the nested hypervisor to skip L1D flush on vmentry") Signed-off-by: Jim Mattson <jmattson@google.com> Reviewed-by: Vipin Sharma <vipinsh@google.com> Reviewed-by: Xiaoyao Li <xiaoyao.li@intel.com> Message-Id: <20220830174947.2182144-1-jmattson@google.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2022-08-30KVM: x86/mmu: count KVM mmu usage in secondary pagetable stats.Yosry Ahmed
Count the pages used by KVM mmu on x86 in memory stats under secondary pagetable stats (e.g. "SecPageTables" in /proc/meminfo) to give better visibility into the memory consumption of KVM mmu in a similar way to how normal user page tables are accounted. Add the inner helper in common KVM, ARM will also use it to count stats in a future commit. Signed-off-by: Yosry Ahmed <yosryahmed@google.com> Reviewed-by: Sean Christopherson <seanjc@google.com> Acked-by: Marc Zyngier <maz@kernel.org> # generic KVM changes Link: https://lore.kernel.org/r/20220823004639.2387269-3-yosryahmed@google.com Link: https://lore.kernel.org/r/20220823004639.2387269-4-yosryahmed@google.com [sean: squash x86 usage to workaround modpost issues] Signed-off-by: Sean Christopherson <seanjc@google.com>
2022-08-24KVM: x86/mmu: fix memoryleak in kvm_mmu_vendor_module_init()Miaohe Lin
When register_shrinker() fails, KVM doesn't release the percpu counter kvm_total_used_mmu_pages leading to memoryleak. Fix this issue by calling percpu_counter_destroy() when register_shrinker() fails. Fixes: ab271bd4dfd5 ("x86: kvm: propagate register_shrinker return code") Signed-off-by: Miaohe Lin <linmiaohe@huawei.com> Link: https://lore.kernel.org/r/20220823063237.47299-1-linmiaohe@huawei.com [sean: tweak shortlog and changelog] Signed-off-by: Sean Christopherson <seanjc@google.com>
2022-08-24KVM: x86/emulator: Fix handing of POP SS to correctly set interruptibilityMichal Luczaj
The emulator checks the wrong variable while setting the CPU interruptibility state, the target segment is embedded in the instruction opcode, not the ModR/M register. Fix the condition. Signed-off-by: Michal Luczaj <mhal@rbox.co> Fixes: a5457e7bcf9a ("KVM: emulate: POP SS triggers a MOV SS shadow too") Cc: stable@vger.kernel.org Link: https://lore.kernel.org/all/20220821215900.1419215-1-mhal@rbox.co Signed-off-by: Sean Christopherson <seanjc@google.com>
2022-08-24kvm: x86: Do proper cleanup if kvm_x86_ops->vm_init() failsJunaid Shahid
If vm_init() fails [which can happen, for instance, if a memory allocation fails during avic_vm_init()], we need to cleanup some state in order to avoid resource leaks. Signed-off-by: Junaid Shahid <junaids@google.com> Link: https://lore.kernel.org/r/20220729224329.323378-1-junaids@google.com Signed-off-by: Sean Christopherson <seanjc@google.com>
2022-08-21asm goto: eradicate CC_HAS_ASM_GOTONick Desaulniers
GCC has supported asm goto since 4.5, and Clang has since version 9.0.0. The minimum supported versions of these tools for the build according to Documentation/process/changes.rst are 5.1 and 11.0.0 respectively. Remove the feature detection script, Kconfig option, and clean up some fallback code that is no longer supported. The removed script was also testing for a GCC specific bug that was fixed in the 4.7 release. Also remove workarounds for bpftrace using clang older than 9.0.0, since other BPF backend fixes are required at this point. Link: https://lore.kernel.org/lkml/CAK7LNATSr=BXKfkdW8f-H5VT_w=xBpT2ZQcZ7rm6JfkdE+QnmA@mail.gmail.com/ Link: http://gcc.gnu.org/bugzilla/show_bug.cgi?id=48637 Acked-by: Borislav Petkov <bp@suse.de> Suggested-by: Masahiro Yamada <masahiroy@kernel.org> Suggested-by: Alexei Starovoitov <alexei.starovoitov@gmail.com> Signed-off-by: Nick Desaulniers <ndesaulniers@google.com> Reviewed-by: Ingo Molnar <mingo@kernel.org> Reviewed-by: Nathan Chancellor <nathan@kernel.org> Reviewed-by: Alexandre Belloni <alexandre.belloni@bootlin.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2022-08-19KVM: VMX: Heed the 'msr' argument in msr_write_intercepted()Jim Mattson
Regardless of the 'msr' argument passed to the VMX version of msr_write_intercepted(), the function always checks to see if a specific MSR (IA32_SPEC_CTRL) is intercepted for write. This behavior seems unintentional and unexpected. Modify the function so that it checks to see if the provided 'msr' index is intercepted for write. Fixes: 67f4b9969c30 ("KVM: nVMX: Handle dynamic MSR intercept toggling") Cc: Sean Christopherson <seanjc@google.com> Signed-off-by: Jim Mattson <jmattson@google.com> Reviewed-by: Sean Christopherson <seanjc@google.com> Message-Id: <20220810213050.2655000-1-jmattson@google.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2022-08-19kvm: x86: mmu: Always flush TLBs when enabling dirty loggingJunaid Shahid
When A/D bits are not available, KVM uses a software access tracking mechanism, which involves making the SPTEs inaccessible. However, the clear_young() MMU notifier does not flush TLBs. So it is possible that there may still be stale, potentially writable, TLB entries. This is usually fine, but can be problematic when enabling dirty logging, because it currently only does a TLB flush if any SPTEs were modified. But if all SPTEs are in access-tracked state, then there won't be a TLB flush, which means that the guest could still possibly write to memory and not have it reflected in the dirty bitmap. So just unconditionally flush the TLBs when enabling dirty logging. As an alternative, KVM could explicitly check the MMU-Writable bit when write-protecting SPTEs to decide if a flush is needed (instead of checking the Writable bit), but given that a flush almost always happens anyway, so just making it unconditional seems simpler. Signed-off-by: Junaid Shahid <junaids@google.com> Message-Id: <20220810224939.2611160-1-junaids@google.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2022-08-19kvm: x86: mmu: Drop the need_remote_flush() functionJunaid Shahid
This is only used by kvm_mmu_pte_write(), which no longer actually creates the new SPTE and instead just clears the old SPTE. So we just need to check if the old SPTE was shadow-present instead of calling need_remote_flush(). Hence we can drop this function. It was incomplete anyway as it didn't take access-tracking into account. This patch should not result in any functional change. Signed-off-by: Junaid Shahid <junaids@google.com> Reviewed-by: David Matlack <dmatlack@google.com> Reviewed-by: Sean Christopherson <seanjc@google.com> Message-Id: <20220723024316.2725328-1-junaids@google.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2022-08-19x86/kvm: Fix "missing ENDBR" BUG for fastop functionsJosh Poimboeuf
The following BUG was reported: traps: Missing ENDBR: andw_ax_dx+0x0/0x10 [kvm] ------------[ cut here ]------------ kernel BUG at arch/x86/kernel/traps.c:253! invalid opcode: 0000 [#1] PREEMPT SMP NOPTI <TASK> asm_exc_control_protection+0x2b/0x30 RIP: 0010:andw_ax_dx+0x0/0x10 [kvm] Code: c3 cc cc cc cc 0f 1f 44 00 00 66 0f 1f 00 48 19 d0 c3 cc cc cc cc 0f 1f 40 00 f3 0f 1e fa 20 d0 c3 cc cc cc cc 0f 1f 44 00 00 <66> 0f 1f 00 66 21 d0 c3 cc cc cc cc 0f 1f 40 00 66 0f 1f 00 21 d0 ? andb_al_dl+0x10/0x10 [kvm] ? fastop+0x5d/0xa0 [kvm] x86_emulate_insn+0x822/0x1060 [kvm] x86_emulate_instruction+0x46f/0x750 [kvm] complete_emulated_mmio+0x216/0x2c0 [kvm] kvm_arch_vcpu_ioctl_run+0x604/0x650 [kvm] kvm_vcpu_ioctl+0x2f4/0x6b0 [kvm] ? wake_up_q+0xa0/0xa0 The BUG occurred because the ENDBR in the andw_ax_dx() fastop function had been incorrectly "sealed" (converted to a NOP) by apply_ibt_endbr(). Objtool marked it to be sealed because KVM has no compile-time references to the function. Instead KVM calculates its address at runtime. Prevent objtool from annotating fastop functions as sealable by creating throwaway dummy compile-time references to the functions. Fixes: 6649fa876da4 ("x86/ibt,kvm: Add ENDBR to fastops") Reported-by: Pengfei Xu <pengfei.xu@intel.com> Debugged-by: Peter Zijlstra <peterz@infradead.org> Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org> Message-Id: <0d4116f90e9d0c1b754bb90c585e6f0415a1c508.1660837839.git.jpoimboe@kernel.org> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2022-08-19x86/kvm: Simplify FOP_SETCC()Josh Poimboeuf
SETCC_ALIGN and FOP_ALIGN are both 16. Remove the special casing for FOP_SETCC() and just make it a normal fastop. Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org> Message-Id: <7c13d94d1a775156f7e36eed30509b274a229140.1660837839.git.jpoimboe@kernel.org> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2022-08-19KVM: Rename mmu_notifier_* to mmu_invalidate_*Chao Peng
The motivation of this renaming is to make these variables and related helper functions less mmu_notifier bound and can also be used for non mmu_notifier based page invalidation. mmu_invalidate_* was chosen to better describe the purpose of 'invalidating' a page that those variables are used for. - mmu_notifier_seq/range_start/range_end are renamed to mmu_invalidate_seq/range_start/range_end. - mmu_notifier_retry{_hva} helper functions are renamed to mmu_invalidate_retry{_hva}. - mmu_notifier_count is renamed to mmu_invalidate_in_progress to avoid confusion with mn_active_invalidate_count. - While here, also update kvm_inc/dec_notifier_count() to kvm_mmu_invalidate_begin/end() to match the change for mmu_notifier_count. No functional change intended. Signed-off-by: Chao Peng <chao.p.peng@linux.intel.com> Message-Id: <20220816125322.1110439-3-chao.p.peng@linux.intel.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2022-08-15x86: Fix various duplicate-word comment typosJason Wang
[ mingo: Consolidated 4 very similar patches into one, it's silly to spread this out. ] Signed-off-by: Jason Wang <wangborong@cdjrlc.com> Signed-off-by: Ingo Molnar <mingo@kernel.org> Signed-off-by: Borislav Petkov <bp@suse.de> Link: https://lore.kernel.org/r/20220715044809.20572-1-wangborong@cdjrlc.com
2022-08-11Merge tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvmLinus Torvalds
Pull more kvm updates from Paolo Bonzini: - Xen timer fixes - Documentation formatting fixes - Make rseq selftest compatible with glibc-2.35 - Fix handling of illegal LEA reg, reg - Cleanup creation of debugfs entries - Fix steal time cache handling bug - Fixes for MMIO caching - Optimize computation of number of LBRs - Fix uninitialized field in guest_maxphyaddr < host_maxphyaddr path * tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm: (26 commits) KVM: x86/MMU: properly format KVM_CAP_VM_DISABLE_NX_HUGE_PAGES capability table Documentation: KVM: extend KVM_CAP_VM_DISABLE_NX_HUGE_PAGES heading underline KVM: VMX: Adjust number of LBR records for PERF_CAPABILITIES at refresh KVM: VMX: Use proper type-safe functions for vCPU => LBRs helpers KVM: x86: Refresh PMU after writes to MSR_IA32_PERF_CAPABILITIES KVM: selftests: Test all possible "invalid" PERF_CAPABILITIES.LBR_FMT vals KVM: selftests: Use getcpu() instead of sched_getcpu() in rseq_test KVM: selftests: Make rseq compatible with glibc-2.35 KVM: Actually create debugfs in kvm_create_vm() KVM: Pass the name of the VM fd to kvm_create_vm_debugfs() KVM: Get an fd before creating the VM KVM: Shove vcpu stats_id init into kvm_vcpu_init() KVM: Shove vm stats_id init into kvm_create_vm() KVM: x86/mmu: Add sanity check that MMIO SPTE mask doesn't overlap gen KVM: x86/mmu: rename trace function name for asynchronous page fault KVM: x86/xen: Stop Xen timer before changing IRQ KVM: x86/xen: Initialize Xen timer only once KVM: SVM: Disable SEV-ES support if MMIO caching is disable KVM: x86/mmu: Fully re-evaluate MMIO caching when SPTE masks change KVM: x86: Tag kvm_mmu_x86_module_init() with __init ...
2022-08-10KVM: VMX: Adjust number of LBR records for PERF_CAPABILITIES at refreshSean Christopherson
Now that the PMU is refreshed when MSR_IA32_PERF_CAPABILITIES is written by host userspace, zero out the number of LBR records for a vCPU during PMU refresh if PMU_CAP_LBR_FMT is not set in PERF_CAPABILITIES instead of handling the check at run-time. guest_cpuid_has() is expensive due to the linear search of guest CPUID entries, intel_pmu_lbr_is_enabled() is checked on every VM-Enter, _and_ simply enumerating the same "Model" as the host causes KVM to set the number of LBR records to a non-zero value. Signed-off-by: Sean Christopherson <seanjc@google.com> Message-Id: <20220727233424.2968356-4-seanjc@google.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2022-08-10KVM: VMX: Use proper type-safe functions for vCPU => LBRs helpersSean Christopherson
Turn vcpu_to_lbr_desc() and vcpu_to_lbr_records() into functions in order to provide type safety, to document exactly what they return, and to allow consuming the helpers in vmx.h. Move the definitions as necessary (the macros "reference" to_vmx() before its definition). No functional change intended. Signed-off-by: Sean Christopherson <seanjc@google.com> Message-Id: <20220727233424.2968356-3-seanjc@google.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2022-08-10KVM: x86: Refresh PMU after writes to MSR_IA32_PERF_CAPABILITIESSean Christopherson
Refresh the PMU if userspace modifies MSR_IA32_PERF_CAPABILITIES. KVM consumes the vCPU's PERF_CAPABILITIES when enumerating PEBS support, but relies on CPUID updates to refresh the PMU. I.e. KVM will do the wrong thing if userspace stuffs PERF_CAPABILITIES _after_ setting guest CPUID. Opportunistically fix a curly-brace indentation. Fixes: c59a1f106f5c ("KVM: x86/pmu: Add IA32_PEBS_ENABLE MSR emulation for extended PEBS") Cc: Like Xu <like.xu.linux@gmail.com> Signed-off-by: Sean Christopherson <seanjc@google.com> Message-Id: <20220727233424.2968356-2-seanjc@google.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2022-08-10KVM: x86/mmu: Add sanity check that MMIO SPTE mask doesn't overlap genSean Christopherson
Add compile-time and init-time sanity checks to ensure that the MMIO SPTE mask doesn't overlap the MMIO SPTE generation or the MMU-present bit. The generation currently avoids using bit 63, but that's as much coincidence as it is strictly necessarly. That will change in the future, as TDX support will require setting bit 63 (SUPPRESS_VE) in the mask. Explicitly carve out the bits that are allowed in the mask so that any future shuffling of SPTE bits doesn't silently break MMIO caching (KVM has broken MMIO caching more than once due to overlapping the generation with other things). Suggested-by: Kai Huang <kai.huang@intel.com> Signed-off-by: Sean Christopherson <seanjc@google.com> Reviewed-by: Kai Huang <kai.huang@intel.com> Message-Id: <20220805194133.86299-1-seanjc@google.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2022-08-10KVM: x86/mmu: rename trace function name for asynchronous page faultMingwei Zhang
Rename the tracepoint function from trace_kvm_async_pf_doublefault() to trace_kvm_async_pf_repeated_fault() to make it clear, since double fault has nothing to do with this trace function. Asynchronous Page Fault (APF) is an artifact generated by KVM when it cannot find a physical page to satisfy an EPT violation. KVM uses APF to tell the guest OS to do something else such as scheduling other guest processes to make forward progress. However, when another guest process also touches a previously APFed page, KVM halts the vCPU instead of generating a repeated APF to avoid wasting cycles. Double fault (#DF) clearly has a different meaning and a different consequence when triggered. #DF requires two nested contributory exceptions instead of two page faults faulting at the same address. A prevous bug on APF indicates that it may trigger a double fault in the guest [1] and clearly this trace function has nothing to do with it. So rename this function should be a valid choice. No functional change intended. [1] https://www.spinics.net/lists/kvm/msg214957.html Signed-off-by: Mingwei Zhang <mizhang@google.com> Message-Id: <20220807052141.69186-1-mizhang@google.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2022-08-10KVM: x86/xen: Stop Xen timer before changing IRQColeman Dietsch
Stop Xen timer (if it's running) prior to changing the IRQ vector and potentially (re)starting the timer. Changing the IRQ vector while the timer is still running can result in KVM injecting a garbage event, e.g. vm_xen_inject_timer_irqs() could see a non-zero xen.timer_pending from a previous timer but inject the new xen.timer_virq. Fixes: 536395260582 ("KVM: x86/xen: handle PV timers oneshot mode") Cc: stable@vger.kernel.org Link: https://syzkaller.appspot.com/bug?id=8234a9dfd3aafbf092cc5a7cd9842e3ebc45fc42 Reported-by: syzbot+e54f930ed78eb0f85281@syzkaller.appspotmail.com Signed-off-by: Coleman Dietsch <dietschc@csp.edu> Reviewed-by: Sean Christopherson <seanjc@google.com> Acked-by: David Woodhouse <dwmw@amazon.co.uk> Message-Id: <20220808190607.323899-3-dietschc@csp.edu> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2022-08-10KVM: x86/xen: Initialize Xen timer only onceColeman Dietsch
Add a check for existing xen timers before initializing a new one. Currently kvm_xen_init_timer() is called on every KVM_XEN_VCPU_ATTR_TYPE_TIMER, which is causing the following ODEBUG crash when vcpu->arch.xen.timer is already set. ODEBUG: init active (active state 0) object type: hrtimer hint: xen_timer_callbac0 RIP: 0010:debug_print_object+0x16e/0x250 lib/debugobjects.c:502 Call Trace: __debug_object_init debug_hrtimer_init debug_init hrtimer_init kvm_xen_init_timer kvm_xen_vcpu_set_attr kvm_arch_vcpu_ioctl kvm_vcpu_ioctl vfs_ioctl Fixes: 536395260582 ("KVM: x86/xen: handle PV timers oneshot mode") Cc: stable@vger.kernel.org Link: https://syzkaller.appspot.com/bug?id=8234a9dfd3aafbf092cc5a7cd9842e3ebc45fc42 Reported-by: syzbot+e54f930ed78eb0f85281@syzkaller.appspotmail.com Signed-off-by: Coleman Dietsch <dietschc@csp.edu> Reviewed-by: Sean Christopherson <seanjc@google.com> Message-Id: <20220808190607.323899-2-dietschc@csp.edu> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2022-08-10KVM: SVM: Disable SEV-ES support if MMIO caching is disableSean Christopherson
Disable SEV-ES if MMIO caching is disabled as SEV-ES relies on MMIO SPTEs generating #NPF(RSVD), which are reflected by the CPU into the guest as a #VC. With SEV-ES, the untrusted host, a.k.a. KVM, doesn't have access to the guest instruction stream or register state and so can't directly emulate in response to a #NPF on an emulated MMIO GPA. Disabling MMIO caching means guest accesses to emulated MMIO ranges cause #NPF(!PRESENT), and those flavors of #NPF cause automatic VM-Exits, not #VC. Adjust KVM's MMIO masks to account for the C-bit location prior to doing SEV(-ES) setup, and document that dependency between adjusting the MMIO SPTE mask and SEV(-ES) setup. Fixes: b09763da4dd8 ("KVM: x86/mmu: Add module param to disable MMIO caching (for testing)") Reported-by: Michael Roth <michael.roth@amd.com> Tested-by: Michael Roth <michael.roth@amd.com> Cc: Tom Lendacky <thomas.lendacky@amd.com> Cc: stable@vger.kernel.org Signed-off-by: Sean Christopherson <seanjc@google.com> Message-Id: <20220803224957.1285926-4-seanjc@google.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2022-08-10KVM: x86/mmu: Fully re-evaluate MMIO caching when SPTE masks changeSean Christopherson
Fully re-evaluate whether or not MMIO caching can be enabled when SPTE masks change; simply clearing enable_mmio_caching when a configuration isn't compatible with caching fails to handle the scenario where the masks are updated, e.g. by VMX for EPT or by SVM to account for the C-bit location, and toggle compatibility from false=>true. Snapshot the original module param so that re-evaluating MMIO caching preserves userspace's desire to allow caching. Use a snapshot approach so that enable_mmio_caching still reflects KVM's actual behavior. Fixes: 8b9e74bfbf8c ("KVM: x86/mmu: Use enable_mmio_caching to track if MMIO caching is enabled") Reported-by: Michael Roth <michael.roth@amd.com> Cc: Tom Lendacky <thomas.lendacky@amd.com> Cc: stable@vger.kernel.org Tested-by: Michael Roth <michael.roth@amd.com> Signed-off-by: Sean Christopherson <seanjc@google.com> Reviewed-by: Kai Huang <kai.huang@intel.com> Message-Id: <20220803224957.1285926-3-seanjc@google.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2022-08-10KVM: x86: Tag kvm_mmu_x86_module_init() with __initSean Christopherson
Mark kvm_mmu_x86_module_init() with __init, the entire reason it exists is to initialize variables when kvm.ko is loaded, i.e. it must never be called after module initialization. Fixes: 1d0e84806047 ("KVM: x86/mmu: Resolve nx_huge_pages when kvm.ko is loaded") Cc: stable@vger.kernel.org Reviewed-by: Kai Huang <kai.huang@intel.com> Tested-by: Michael Roth <michael.roth@amd.com> Signed-off-by: Sean Christopherson <seanjc@google.com> Message-Id: <20220803224957.1285926-2-seanjc@google.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2022-08-10KVM: x86: emulator: Fix illegal LEA handlingMichal Luczaj
The emulator mishandles LEA with register source operand. Even though such LEA is illegal, it can be encoded and fed to CPU. In which case real hardware throws #UD. The emulator, instead, returns address of x86_emulate_ctxt._regs. This info leak hurts host's kASLR. Tell the decoder that illegal LEA is not to be emulated. Signed-off-by: Michal Luczaj <mhal@rbox.co> Message-Id: <20220729134801.1120-1-mhal@rbox.co> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2022-08-10KVM: X86: avoid uninitialized 'fault.async_page_fault' from fixed-up #PFYu Zhang
kvm_fixup_and_inject_pf_error() was introduced to fixup the error code( e.g., to add RSVD flag) and inject the #PF to the guest, when guest MAXPHYADDR is smaller than the host one. When it comes to nested, L0 is expected to intercept and fix up the #PF and then inject to L2 directly if - L2.MAXPHYADDR < L0.MAXPHYADDR and - L1 has no intention to intercept L2's #PF (e.g., L2 and L1 have the same MAXPHYADDR value && L1 is using EPT for L2), instead of constructing a #PF VM Exit to L1. Currently, with PFEC_MASK and PFEC_MATCH both set to 0 in vmcs02, the interception and injection may happen on all L2 #PFs. However, failing to initialize 'fault' in kvm_fixup_and_inject_pf_error() may cause the fault.async_page_fault being NOT zeroed, and later the #PF being treated as a nested async page fault, and then being injected to L1. Instead of zeroing 'fault' at the beginning of this function, we mannually set the value of 'fault.async_page_fault', because false is the value we really expect. Fixes: 897861479c064 ("KVM: x86: Add helper functions for illegal GPA checking and page fault injection") Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=216178 Reported-by: Yang Lixiao <lixiao.yang@intel.com> Signed-off-by: Yu Zhang <yu.c.zhang@linux.intel.com> Reviewed-by: Sean Christopherson <seanjc@google.com> Message-Id: <20220718074756.53788-1-yu.c.zhang@linux.intel.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2022-08-10KVM: x86: Bug the VM if an accelerated x2APIC trap occurs on a "bad" regSean Christopherson
Bug the VM if retrieving the x2APIC MSR/register while processing an accelerated vAPIC trap VM-Exit fails. In theory it's impossible for the lookup to fail as hardware has already validated the register, but bugs happen, and not checking the result of kvm_lapic_msr_read() would result in consuming the uninitialized "val" if a KVM or hardware bug occurs. Fixes: 1bd9dfec9fd4 ("KVM: x86: Do not block APIC write for non ICR registers") Reported-by: Dan Carpenter <dan.carpenter@oracle.com> Cc: Suravee Suthikulpanit <suravee.suthikulpanit@amd.com> Signed-off-by: Sean Christopherson <seanjc@google.com> Message-Id: <20220804235028.1766253-1-seanjc@google.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2022-08-10KVM: x86: do not report preemption if the steal time cache is stalePaolo Bonzini
Commit 7e2175ebd695 ("KVM: x86: Fix recording of guest steal time / preempted status", 2021-11-11) open coded the previous call to kvm_map_gfn, but in doing so it dropped the comparison between the cached guest physical address and the one in the MSR. This cause an incorrect cache hit if the guest modifies the steal time address while the memslots remain the same. This can happen with kexec, in which case the preempted bit is written at the address used by the old kernel instead of the old one. Cc: David Woodhouse <dwmw@amazon.co.uk> Cc: stable@vger.kernel.org Fixes: 7e2175ebd695 ("KVM: x86: Fix recording of guest steal time / preempted status") Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
generated by cgit (git 2.34.1) at 2025-09-23 06:24:07 +0000