Drop code to initialize XCR0 during fx_init(), a.k.a. vCPU creation, as
XCR0 has been initialized during kvm_vcpu_reset() (for RESET) since
commit a554d207dc46 ("KVM: X86: Processor States following Reset or INIT").
Back when XCR0 support was added by commit 2acf923e38fb ("KVM: VMX:
Enable XSAVE/XRSTOR for guest"), KVM didn't differentiate between RESET
and INIT. Ignoring the fact that calling fx_init() for INIT is obviously
wrong, e.g. FPU state after INIT is not the same as after RESET, setting
XCR0 in fx_init() was correct.
Eventually fx_init() got moved to kvm_arch_vcpu_init(), a.k.a. vCPU
creation (ignore the terrible name) by commit 0ee6a5172573 ("x86/fpu,
kvm: Simplify fx_init()"). Finally, commit 95a0d01eef7a ("KVM: x86: Move
all vcpu init code into kvm_arch_vcpu_create()") killed off
kvm_arch_vcpu_init(), leaving behind the oddity of redundant setting of
guest state during vCPU creation.
No functional change intended.
Signed-off-by: Sean Christopherson <seanjc@xxxxxxxxxx>
---
arch/x86/kvm/x86.c | 7 +------
1 file changed, 1 insertion(+), 6 deletions(-)
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index e0bff5473813..6fd3fe21863e 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -993,7 +993,7 @@ static int __kvm_set_xcr(struct kvm_vcpu *vcpu, u32 index, u64 xcr)
/*
* Do not allow the guest to set bits that we do not support
* saving. However, xcr0 bit 0 is always set, even if the
- * emulated CPU does not support XSAVE (see fx_init).
+ * emulated CPU does not support XSAVE (see kvm_vcpu_reset()).
*/
valid_bits = vcpu->arch.guest_supported_xcr0 | XFEATURE_MASK_FP;
if (xcr0 & ~valid_bits)
@@ -10623,11 +10623,6 @@ static void fx_init(struct kvm_vcpu *vcpu)
if (boot_cpu_has(X86_FEATURE_XSAVES))
vcpu->arch.guest_fpu->state.xsave.header.xcomp_bv =
host_xcr0 | XSTATE_COMPACTION_ENABLED;
-
- /*
- * Ensure guest xcr0 is valid for loading
- */
- vcpu->arch.xcr0 = XFEATURE_MASK_FP;
}
void kvm_free_guest_fpu(struct kvm_vcpu *vcpu)
--
2.33.0.464.g1972c5931b-goog
