From: Mushahid Hussain <[email protected]> mcg_cap is per vCPU. kvm_arch_vcpu_create() gives every vCPU the KVM_MAX_MCE_BANKS default, plane twins included, but KVM_X86_SETUP_MCE was only accepted on the plane-0 fd: userspace programs plane 0 and a higher plane keeps running with the default, so the MCG view diverges across planes. Hyper-V defines the MCG state as shared across Virtual Trust Levels, so userspace needs to program the same value on every plane: accept the ioctl on plane vCPUs.
Assisted-by: LLM [dwmw2: ours gates plane vCPU fd ioctls in kvm_arch_is_vcpu_plane_ioctl() in the same shape; same one-line addition.] (re-done by hand) Signed-off-by: David Woodhouse <[email protected]> --- Documentation/virt/kvm/api.rst | 2 +- arch/x86/kvm/x86.c | 1 + 2 files changed, 2 insertions(+), 1 deletion(-) diff --git a/Documentation/virt/kvm/api.rst b/Documentation/virt/kvm/api.rst index 494600236360..24050c79d95c 100644 --- a/Documentation/virt/kvm/api.rst +++ b/Documentation/virt/kvm/api.rst @@ -4594,7 +4594,7 @@ capabilities will have the corresponding bits set. :Capability: KVM_CAP_MCE :Architectures: x86 -:Type: vcpu ioctl +:Type: vcpu ioctl (all planes) :Parameters: u64 mcg_cap (in) :Returns: 0 on success, -EFAULT if u64 mcg_cap cannot be read, diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index dc6196107c23..e2e54f06b092 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -6400,6 +6400,7 @@ bool kvm_arch_is_vcpu_plane_ioctl(unsigned ioctl) case KVM_SET_XSAVE: case KVM_GET_REG_LIST: case KVM_TRANSLATE: + case KVM_X86_SETUP_MCE: return true; default: return false; -- 2.50.1
