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path: root/arch/riscv/include/asm/kvm_vcpu_sbi.h
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2025-05-21RISC-V: KVM: add KVM_CAP_RISCV_MP_STATE_RESETRadim Krčmář
Add a toggleable VM capability to reset the VCPU from userspace by setting MP_STATE_INIT_RECEIVED through IOCTL. Reset through a mp_state to avoid adding a new IOCTL. Do not reset on a transition from STOPPED to RUNNABLE, because it's better to avoid side effects that would complicate userspace adoption. The MP_STATE_INIT_RECEIVED is not a permanent mp_state -- IOCTL resets the VCPU while preserving the original mp_state -- because we wouldn't gain much from having a new state it in the rest of KVM, but it's a very non-standard use of the IOCTL. Signed-off-by: Radim Krčmář <rkrcmar@ventanamicro.com> Reviewed-by: Anup Patel <anup@brainfault.org> Link: https://lore.kernel.org/r/20250515143723.2450630-5-rkrcmar@ventanamicro.com Signed-off-by: Anup Patel <anup@brainfault.org>
2025-05-21KVM: RISC-V: refactor sbi reset requestRadim Krčmář
The same code is used twice and SBI reset sets only two variables. Reviewed-by: Andrew Jones <ajones@ventanamicro.com> Signed-off-by: Radim Krčmář <rkrcmar@ventanamicro.com> Link: https://lore.kernel.org/r/20250403112522.1566629-5-rkrcmar@ventanamicro.com 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>
2023-12-30RISC-V: KVM: Add support for SBI STA registersAndrew Jones
KVM userspace needs to be able to save and restore the steal-time shared memory address. Provide the address through the get/set-one-reg interface with two ulong-sized SBI STA extension registers (lo and hi). 64-bit KVM userspace must not set the hi register to anything other than zero and is allowed to completely neglect saving/restoring it. Reviewed-by: Anup Patel <anup@brainfault.org> Signed-off-by: Andrew Jones <ajones@ventanamicro.com> Signed-off-by: Anup Patel <anup@brainfault.org>
2023-12-30RISC-V: KVM: Add support for SBI extension registersAndrew Jones
Some SBI extensions have state that needs to be saved / restored when migrating the VM. Provide a get/set-one-reg register type for SBI extension registers. Each SBI extension that uses this type will have its own subtype. There are currently no subtypes defined. The next patch introduces the first one. Reviewed-by: Anup Patel <anup@brainfault.org> Reviewed-by: Atish Patra <atishp@rivosinc.com> Signed-off-by: Andrew Jones <ajones@ventanamicro.com> Signed-off-by: Anup Patel <anup@brainfault.org>
2023-12-30RISC-V: KVM: Add SBI STA extension skeletonAndrew Jones
Add the files and functions needed to support the SBI STA (steal-time accounting) extension. In the next patches we'll complete the functions to fully enable SBI STA support. Reviewed-by: Anup Patel <anup@brainfault.org> Reviewed-by: Atish Patra <atishp@rivosinc.com> Signed-off-by: Andrew Jones <ajones@ventanamicro.com> Signed-off-by: Anup Patel <anup@brainfault.org>
2023-12-29RISC-V: KVM: Make SBI uapi consistent with ISA uapiAndrew Jones
When an SBI extension cannot be enabled, that's a distinct state vs. enabled and disabled. Modify enum kvm_riscv_sbi_ext_status to accommodate it, which allows KVM userspace to tell the difference in state too, as the SBI extension register will disappear when it cannot be enabled, i.e. accesses to it return ENOENT. get-reg-list is updated as well to only add SBI extension registers to the list which may be enabled. Returning ENOENT for SBI extension registers which cannot be enabled makes them consistent with ISA extension registers. Any SBI extensions which were enabled by default are still enabled by default, if they can be enabled at all. Signed-off-by: Andrew Jones <ajones@ventanamicro.com> Reviewed-by: Anup Patel <anup@brainfault.org> Signed-off-by: Anup Patel <anup@brainfault.org>
2023-10-20RISC-V: KVM: Forward SBI DBCN extension to user-spaceAnup Patel
The frozen SBI v2.0 specification defines the SBI debug console (DBCN) extension which replaces the legacy SBI v0.1 console functions namely sbi_console_getchar() and sbi_console_putchar(). The SBI DBCN extension needs to be emulated in the KVM user-space (i.e. QEMU-KVM or KVMTOOL) so we forward SBI DBCN calls from KVM guest to the KVM user-space which can then redirect the console input/output to wherever it wants (e.g. telnet, file, stdio, etc). The SBI debug console is simply a early console available to KVM guest for early prints and it does not intend to replace the proper console devices such as 8250, VirtIO console, etc. Signed-off-by: Anup Patel <apatel@ventanamicro.com> Reviewed-by: Andrew Jones <ajones@ventanamicro.com> Signed-off-by: Anup Patel <anup@brainfault.org>
2023-10-20RISC-V: KVM: Allow some SBI extensions to be disabled by defaultAnup Patel
Currently, all SBI extensions are enabled by default which is problematic for SBI extensions (such as DBCN) which are forwarded to the KVM user-space because we might have an older KVM user-space which is not aware/ready to handle newer SBI extensions. Ideally, the SBI extensions forwarded to the KVM user-space must be disabled by default. To address above, we allow certain SBI extensions to be disabled by default so that KVM user-space must explicitly enable such SBI extensions to receive forwarded calls from Guest VCPU. Signed-off-by: Anup Patel <apatel@ventanamicro.com> Reviewed-by: Andrew Jones <ajones@ventanamicro.com> Signed-off-by: Anup Patel <anup@brainfault.org>
2023-10-20RISC-V: KVM: Change the SBI specification version to v2.0Anup Patel
We will be implementing SBI DBCN extension for KVM RISC-V so let us change the KVM RISC-V SBI specification version to v2.0. Signed-off-by: Anup Patel <apatel@ventanamicro.com> Reviewed-by: Andrew Jones <ajones@ventanamicro.com> Signed-off-by: Anup Patel <anup@brainfault.org>
2023-06-19riscv: kvm: define vcpu_sbi_ext_pmu in headerBen Dooks
Sparse is giving a warning about vcpu_sbi_ext_pmu not being defined, so add a definition to the relevant header to fix the following: arch/riscv/kvm/vcpu_sbi_pmu.c:81:37: warning: symbol 'vcpu_sbi_ext_pmu' was not declared. Should it be static? Fixes: cbddc4c4cb9e ("RISC-V: KVM: Add SBI PMU extension support") Signed-off-by: Ben Dooks <ben.dooks@codethink.co.uk> Reviewed-by: Anup Patel <anup@brainfault.org> Reviewed-by: Conor Dooley <conor.dooley@microchip.com> Signed-off-by: Anup Patel <anup@brainfault.org>
2023-06-06RISC-V: KVM: Probe for SBI extension statusAndrew Jones
Rather than defaulting the status to available and allowing the user to set availability, default to uninitialized and only allow the user to set the status to unavailable. Then, when an extension is first used, ensure it is available by invoking its probe function, if it has one (an extension is assumed available if it doesn't have a probe function). Checking the status in kvm_vcpu_sbi_find_ext() ensures extension functions cannot be invoked when they're unavailable. Signed-off-by: Andrew Jones <ajones@ventanamicro.com> Reviewed-by: Anup Patel <anup@brainfault.org> Signed-off-by: Anup Patel <anup@brainfault.org>
2023-06-06RISC-V: KVM: Convert extension_disabled[] to ext_status[]Andrew Jones
Change the boolean extension_disabled[] array to an array of enums, ext_status[]. For now, the enum only has two states, which correspond to the previous boolean states, so this patch has no intended functional change. The next patch will add another state, expanding the purpose of ext_status[]. Signed-off-by: Andrew Jones <ajones@ventanamicro.com> Reviewed-by: Anup Patel <anup@brainfault.org> Signed-off-by: Anup Patel <anup@brainfault.org>
2023-04-21RISC-V: KVM: Add ONE_REG interface to enable/disable SBI extensionsAnup Patel
We add ONE_REG interface to enable/disable SBI extensions (just like the ONE_REG interface for ISA extensions). This allows KVM user-space to decide the set of SBI extension enabled for a Guest and by default all SBI extensions are enabled. Signed-off-by: Anup Patel <apatel@ventanamicro.com> Reviewed-by: Andrew Jones <ajones@ventanamicro.com> Signed-off-by: Anup Patel <anup@brainfault.org>
2023-02-07RISC-V: KVM: Modify SBI extension handler to return SBI error codeAtish Patra
Currently, the SBI extension handle is expected to return Linux error code. The top SBI layer converts the Linux error code to SBI specific error code that can be returned to guest invoking the SBI calls. This model works as long as SBI error codes have 1-to-1 mappings between them. However, that may not be true always. This patch attempts to disassociate both these error codes by allowing the SBI extension implementation to return SBI specific error codes as well. The extension will continue to return the Linux error specific code which will indicate any problem *with* the extension emulation while the SBI specific error will indicate the problem *of* the emulation. Reviewed-by: Anup Patel <anup@brainfault.org> Reviewed-by: Andrew Jones <ajones@ventanamicro.com> Suggested-by: Andrew Jones <ajones@ventanamicro.com> Signed-off-by: Atish Patra <atishp@rivosinc.com> Signed-off-by: Anup Patel <anup@brainfault.org>
2023-02-07RISC-V: KVM: Define a probe function for SBI extension data structuresAtish Patra
Currently the probe function just checks if an SBI extension is registered or not. However, the extension may not want to advertise itself depending on some other condition. An additional extension specific probe function will allow extensions to decide if they want to be advertised to the caller or not. Any extension that does not require additional dependency checks can avoid implementing this function. Reviewed-by: Anup Patel <anup@brainfault.org> Reviewed-by: Andrew Jones <ajones@ventanamicro.com> Signed-off-by: Atish Patra <atishp@rivosinc.com> Signed-off-by: Anup Patel <anup@brainfault.org>
2022-12-07RISC-V: KVM: Move sbi related struct and functions to kvm_vcpu_sbi.hAnup Patel
Just like asm/kvm_vcpu_timer.h, we should have all sbi related struct and functions in asm/kvm_vcpu_sbi.h. Signed-off-by: Anup Patel <apatel@ventanamicro.com> Reviewed-by: Atish Patra <atishp@rivosinc.com> Reviewed-by: Andrew Jones <ajones@ventanamicro.com> Signed-off-by: Anup Patel <anup@brainfault.org>
2022-10-02RISC-V: KVM: Change the SBI specification version to v1.0Anup Patel
The SBI v1.0 specificaiton is functionally same as SBI v0.3 specification except that SBI v1.0 specification went through the full RISC-V International ratification process. Let us change the SBI specification version to v1.0. Signed-off-by: Anup Patel <apatel@ventanamicro.com> Reviewed-by: Atish Patra <atishp@rivosinc.com> Signed-off-by: Anup Patel <anup@brainfault.org>
2022-08-19riscv: kvm: move extern sbi_ext declarations to a headerConor Dooley
Sparse complains about missing statics in the declarations of several variables: arch/riscv/kvm/vcpu_sbi_replace.c:38:37: warning: symbol 'vcpu_sbi_ext_time' was not declared. Should it be static? arch/riscv/kvm/vcpu_sbi_replace.c:73:37: warning: symbol 'vcpu_sbi_ext_ipi' was not declared. Should it be static? arch/riscv/kvm/vcpu_sbi_replace.c:126:37: warning: symbol 'vcpu_sbi_ext_rfence' was not declared. Should it be static? arch/riscv/kvm/vcpu_sbi_replace.c:170:37: warning: symbol 'vcpu_sbi_ext_srst' was not declared. Should it be static? arch/riscv/kvm/vcpu_sbi_base.c:69:37: warning: symbol 'vcpu_sbi_ext_base' was not declared. Should it be static? arch/riscv/kvm/vcpu_sbi_base.c:90:37: warning: symbol 'vcpu_sbi_ext_experimental' was not declared. Should it be static? arch/riscv/kvm/vcpu_sbi_base.c:96:37: warning: symbol 'vcpu_sbi_ext_vendor' was not declared. Should it be static? arch/riscv/kvm/vcpu_sbi_hsm.c:115:37: warning: symbol 'vcpu_sbi_ext_hsm' was not declared. Should it be static? These variables are however used in vcpu_sbi.c where they are declared as extern. Move them to kvm_vcpu_sbi.h which is handily already included by the three other files. Fixes: a046c2d8578c ("RISC-V: KVM: Reorganize SBI code by moving SBI v0.1 to its own file") Fixes: 5f862df5585c ("RISC-V: KVM: Add v0.1 replacement SBI extensions defined in v0.2") Fixes: 3e1d86569c21 ("RISC-V: KVM: Add SBI HSM extension in KVM") Reviewed-by: Palmer Dabbelt <palmer@rivosinc.com> Signed-off-by: Conor Dooley <conor.dooley@microchip.com> Signed-off-by: Anup Patel <anup@brainfault.org>
2022-03-11RISC-V: KVM: Add common kvm_riscv_vcpu_sbi_system_reset() functionAnup Patel
We rename kvm_sbi_system_shutdown() to kvm_riscv_vcpu_sbi_system_reset() and move it to vcpu_sbi.c so that it can be shared by SBI v0.1 shutdown and SBI v0.3 SRST extension. Signed-off-by: Anup Patel <apatel@ventanamicro.com> Reviewed-by: Atish Patra <atishp@rivosinc.com> Signed-off-by: Anup Patel <anup@brainfault.org>
2022-03-11RISC-V: KVM: Upgrade SBI spec version to v0.3Anup Patel
We upgrade SBI spec version implemented by KVM RISC-V to v0.3 so that Guest kernel can probe and use SBI extensions added by the SBI v0.3 specification. Signed-off-by: Anup Patel <apatel@ventanamicro.com> Reviewed-by: Atish Patra <atishp@rivosinc.com> Signed-off-by: Anup Patel <anup@brainfault.org>
2022-01-06RISC-V: KVM: Add SBI v0.2 base extensionAtish Patra
SBI v0.2 base extension defined to allow backward compatibility and probing of future extensions. This is also the only mandatory SBI extension that must be implemented by SBI implementors. Signed-off-by: Atish Patra <atish.patra@wdc.com> Signed-off-by: Atish Patra <atishp@rivosinc.com> Signed-off-by: Anup Patel <anup.patel@wdc.com>
2022-01-06RISC-V: KVM: Reorganize SBI code by moving SBI v0.1 to its own fileAtish Patra
With SBI v0.2, there may be more SBI extensions in future. It makes more sense to group related extensions in separate files. Guest kernel will choose appropriate SBI version dynamically. Move the existing implementation to a separate file so that it can be removed in future without much conflict. Signed-off-by: Atish Patra <atish.patra@wdc.com> Signed-off-by: Atish Patra <atishp@rivosinc.com> Signed-off-by: Anup Patel <anup.patel@wdc.com>
2022-01-06RISC-V: KVM: Mark the existing SBI implementation as v0.1Atish Patra
The existing SBI specification impelementation follows v0.1 specification. The latest specification allows more scalability and performance improvements. Rename the existing implementation as v0.1 and provide a way to allow future extensions. Signed-off-by: Atish Patra <atish.patra@wdc.com> Signed-off-by: Atish Patra <atishp@rivosinc.com> Signed-off-by: Anup Patel <anup.patel@wdc.com>