Pass XFD_ERR via KVM's exception payload mechanism when injecting an #NM
after interception so that XFD_ERR can be propagated to FRED's event_data
field without needing a dedicated field (which would need to be migrated).
For non-FRED vCPUs, this is a glorified NOP as
kvm_deliver_exception_payload() will simply do nothing (which is desirable
and correct).
Signed-off-by: Sean Christopherson <seanjc@xxxxxxxxxx>
---
arch/x86/kvm/vmx/vmx.c | 14 ++++++++++----
1 file changed, 10 insertions(+), 4 deletions(-)
diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c
index d916199f1e60..f0643aa1f4ef 100644
--- a/arch/x86/kvm/vmx/vmx.c
+++ b/arch/x86/kvm/vmx/vmx.c
@@ -5316,6 +5316,12 @@ bool vmx_guest_inject_ac(struct kvm_vcpu *vcpu)
(kvm_get_rflags(vcpu) & X86_EFLAGS_AC);
}
+static bool is_xfd_nm_fault(struct kvm_vcpu *vcpu)
+{
+ return vcpu->arch.guest_fpu.fpstate->xfd &&
+ !kvm_is_cr0_bit_set(vcpu, X86_CR0_TS);
+}
+
static int handle_exception_nmi(struct kvm_vcpu *vcpu)
{
struct vcpu_vmx *vmx = to_vmx(vcpu);
@@ -5342,7 +5348,8 @@ static int handle_exception_nmi(struct kvm_vcpu *vcpu)
* point.
*/
if (is_nm_fault(intr_info)) {
- kvm_queue_exception(vcpu, NM_VECTOR);
+ kvm_queue_exception_p(vcpu, NM_VECTOR,
+ is_xfd_nm_fault(vcpu) ? vcpu->arch.guest_fpu.xfd_err : 0);
return 1;
}
@@ -7075,14 +7082,13 @@ static void handle_nm_fault_irqoff(struct kvm_vcpu *vcpu)
*
* Update the guest's XFD_ERR if and only if XFD is enabled, as the #NM
* interception may have been caused by L1 interception. Per the SDM,
- * XFD_ERR is not modified if CR0.TS=1.
+ * XFD_ERR is not modified for non-XFD #NM, i.e. if CR0.TS=1.
*
* Note, XFD_ERR is updated _before_ the #NM interception check, i.e.
* unlike CR2 and DR6, the value is not a payload that is attached to
* the #NM exception.
*/
- if (vcpu->arch.guest_fpu.fpstate->xfd &&
- !kvm_is_cr0_bit_set(vcpu, X86_CR0_TS))
+ if (is_xfd_nm_fault(vcpu))
rdmsrl(MSR_IA32_XFD_ERR, vcpu->arch.guest_fpu.xfd_err);
}
--
2.45.2.627.g7a2c4fd464-goog
--BjJMh3azNcbdNTca
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filename="0015-KVM-VMX-Virtualize-FRED-event_data.patch"
