6.12-stable review patch. If anyone has any objections, please let me know.
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From: Paolo Bonzini pbonzini@redhat.com
commit 74c1807f6c4feddb3c3cb1056c54531d4adbaea6 upstream.
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 Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- arch/x86/kvm/x86.c | 15 +++++++++++---- 1 file changed, 11 insertions(+), 4 deletions(-)
--- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -4590,6 +4590,11 @@ static bool kvm_is_vm_type_supported(uns 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; @@ -4698,7 +4703,7 @@ int kvm_vm_ioctl_check_extension(struct 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; @@ -11470,6 +11475,7 @@ int kvm_arch_vcpu_ioctl_run(struct kvm_v { 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); @@ -11515,8 +11521,9 @@ int kvm_arch_vcpu_ioctl_run(struct kvm_v 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; } @@ -11574,7 +11581,7 @@ int kvm_arch_vcpu_ioctl_run(struct kvm_v
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);