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| author |   Paolo Bonzini <pbonzini@redhat.com> | 2025-03-06 21:29:22 +0100 |
|---|---|---|
| committer | Paolo Bonzini <pbonzini@redhat.com> | 2025-03-14 14:20:03 -0400 |
| commit | 74c1807f6c4feddb3c3cb1056c54531d4adbaea6 (patch) | |
| tree | e39bef76c21a6af069d528e18e1a4dc568886712 | |
| parent | KVM: x86: Add infrastructure for secure TSC (diff) | |
| download | wireguard-linux-74c1807f6c4feddb3c3cb1056c54531d4adbaea6.tar.xz wireguard-linux-74c1807f6c4feddb3c3cb1056c54531d4adbaea6.zip | |
KVM: x86: block KVM_CAP_SYNC_REGS if guest state is protected
KVM_CAP_SYNC_REGS does not make sense for VMs with protected guest state,
since the register values cannot actually be written. Return 0
when using the VM-level KVM_CHECK_EXTENSION ioctl, and accordingly
return -EINVAL from KVM_RUN if the valid/dirty fields are nonzero.
However, on exit from KVM_RUN userspace could have placed a nonzero
value into kvm_run->kvm_valid_regs, so check guest_state_protected
again and skip store_regs() in that case.
Cc: stable@vger.kernel.org
Fixes: 517987e3fb19 ("KVM: x86: add fields to struct kvm_arch for CoCo features")
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Message-ID: <20250306202923.646075-1-pbonzini@redhat.com>
Reviewed-by: Pankaj Gupta <pankaj.gupta@amd.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
| -rw-r--r-- | arch/x86/kvm/x86.c | 15 |
1 files changed, 11 insertions, 4 deletions
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index 053547fc6f89..eceb97734646 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -4580,6 +4580,11 @@ static bool kvm_is_vm_type_supported(unsigned long type) return type < 32 && (kvm_caps.supported_vm_types & BIT(type)); } +static inline u32 kvm_sync_valid_fields(struct kvm *kvm) +{ + return kvm && kvm->arch.has_protected_state ? 0 : KVM_SYNC_X86_VALID_FIELDS; +} + int kvm_vm_ioctl_check_extension(struct kvm *kvm, long ext) { int r = 0; @@ -4688,7 +4693,7 @@ int kvm_vm_ioctl_check_extension(struct kvm *kvm, long ext) break; #endif case KVM_CAP_SYNC_REGS: - r = KVM_SYNC_X86_VALID_FIELDS; + r = kvm_sync_valid_fields(kvm); break; case KVM_CAP_ADJUST_CLOCK: r = KVM_CLOCK_VALID_FLAGS; @@ -11481,6 +11486,7 @@ int kvm_arch_vcpu_ioctl_run(struct kvm_vcpu *vcpu) { struct kvm_queued_exception *ex = &vcpu->arch.exception; struct kvm_run *kvm_run = vcpu->run; + u32 sync_valid_fields; int r; r = kvm_mmu_post_init_vm(vcpu->kvm); @@ -11526,8 +11532,9 @@ int kvm_arch_vcpu_ioctl_run(struct kvm_vcpu *vcpu) goto out; } - if ((kvm_run->kvm_valid_regs & ~KVM_SYNC_X86_VALID_FIELDS) || - (kvm_run->kvm_dirty_regs & ~KVM_SYNC_X86_VALID_FIELDS)) { + sync_valid_fields = kvm_sync_valid_fields(vcpu->kvm); + if ((kvm_run->kvm_valid_regs & ~sync_valid_fields) || + (kvm_run->kvm_dirty_regs & ~sync_valid_fields)) { r = -EINVAL; goto out; } @@ -11585,7 +11592,7 @@ int kvm_arch_vcpu_ioctl_run(struct kvm_vcpu *vcpu) out: kvm_put_guest_fpu(vcpu); - if (kvm_run->kvm_valid_regs) + if (kvm_run->kvm_valid_regs && likely(!vcpu->arch.guest_state_protected)) store_regs(vcpu); post_kvm_run_save(vcpu); kvm_vcpu_srcu_read_unlock(vcpu); |