diff options
| author | Yang Weijiang <weijiang.yang@intel.com> | 2025-09-19 15:32:11 -0700 |
|---|---|---|
| committer | Sean Christopherson <seanjc@google.com> | 2025-09-23 09:00:44 -0700 |
| commit | 06f2969c6a1237f05f8ba4324b6ddc2570a808d0 (patch) | |
| tree | adc1aa8bf1eb3a219d11aa009435ab471fe626e3 /arch/x86/include | |
| parent | KVM: x86: Merge 'selftests' into 'cet' to pick up ex_str() (diff) | |
| download | linux-06f2969c6a1237f05f8ba4324b6ddc2570a808d0.tar.gz linux-06f2969c6a1237f05f8ba4324b6ddc2570a808d0.zip | |
KVM: x86: Introduce KVM_{G,S}ET_ONE_REG uAPIs support
Enable KVM_{G,S}ET_ONE_REG uAPIs so that userspace can access MSRs and
other non-MSR registers through them, along with support for
KVM_GET_REG_LIST to enumerate support for KVM-defined registers.
This is in preparation for allowing userspace to read/write the guest SSP
register, which is needed for the upcoming CET virtualization support.
Currently, two types of registers are supported: KVM_X86_REG_TYPE_MSR and
KVM_X86_REG_TYPE_KVM. All MSRs are in the former type; the latter type is
added for registers that lack existing KVM uAPIs to access them. The "KVM"
in the name is intended to be vague to give KVM flexibility to include
other potential registers. More precise names like "SYNTHETIC" and
"SYNTHETIC_MSR" were considered, but were deemed too confusing (e.g. can
be conflated with synthetic guest-visible MSRs) and may put KVM into a
corner (e.g. if KVM wants to change how a KVM-defined register is modeled
internally).
Enumerate only KVM-defined registers in KVM_GET_REG_LIST to avoid
duplicating KVM_GET_MSR_INDEX_LIST, and so that KVM can return _only_
registers that are fully supported (KVM_GET_REG_LIST is vCPU-scoped, i.e.
can be precise, whereas KVM_GET_MSR_INDEX_LIST is system-scoped).
Suggested-by: Sean Christopherson <seanjc@google.com>
Signed-off-by: Yang Weijiang <weijiang.yang@intel.com>
Link: https://lore.kernel.org/all/20240219074733.122080-18-weijiang.yang@intel.com [1]
Tested-by: Mathias Krause <minipli@grsecurity.net>
Tested-by: John Allen <john.allen@amd.com>
Tested-by: Rick Edgecombe <rick.p.edgecombe@intel.com>
Signed-off-by: Chao Gao <chao.gao@intel.com>
Reviewed-by: Binbin Wu <binbin.wu@linux.intel.com>
Reviewed-by: Xiaoyao Li <xiaoyao.li@intel.com>
Co-developed-by: Sean Christopherson <seanjc@google.com>
Link: https://lore.kernel.org/r/20250919223258.1604852-5-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
Diffstat (limited to 'arch/x86/include')
| -rw-r--r-- | arch/x86/include/uapi/asm/kvm.h | 26 |
1 files changed, 26 insertions, 0 deletions
diff --git a/arch/x86/include/uapi/asm/kvm.h b/arch/x86/include/uapi/asm/kvm.h index 0f15d683817d..aae1033c8afa 100644 --- a/arch/x86/include/uapi/asm/kvm.h +++ b/arch/x86/include/uapi/asm/kvm.h @@ -411,6 +411,32 @@ struct kvm_xcrs { __u64 padding[16]; }; +#define KVM_X86_REG_TYPE_MSR 2 +#define KVM_X86_REG_TYPE_KVM 3 + +#define KVM_X86_KVM_REG_SIZE(reg) \ +({ \ + reg == KVM_REG_GUEST_SSP ? KVM_REG_SIZE_U64 : 0; \ +}) + +#define KVM_X86_REG_TYPE_SIZE(type, reg) \ +({ \ + __u64 type_size = (__u64)type << 32; \ + \ + type_size |= type == KVM_X86_REG_TYPE_MSR ? KVM_REG_SIZE_U64 : \ + type == KVM_X86_REG_TYPE_KVM ? KVM_X86_KVM_REG_SIZE(reg) : \ + 0; \ + type_size; \ +}) + +#define KVM_X86_REG_ID(type, index) \ + (KVM_REG_X86 | KVM_X86_REG_TYPE_SIZE(type, index) | index) + +#define KVM_X86_REG_MSR(index) \ + KVM_X86_REG_ID(KVM_X86_REG_TYPE_MSR, index) +#define KVM_X86_REG_KVM(index) \ + KVM_X86_REG_ID(KVM_X86_REG_TYPE_KVM, index) + #define KVM_SYNC_X86_REGS (1UL << 0) #define KVM_SYNC_X86_SREGS (1UL << 1) #define KVM_SYNC_X86_EVENTS (1UL << 2) |