On 1/17/22 09:26, Like Xu wrote:
From: Like Xu <likexu@xxxxxxxxxxx>
XCR0 is reset to 1 by RESET but not INIT and IA32_XSS is zeroed by
both RESET and INIT. In both cases, the size in bytes of the XSAVE
area containing all states enabled by XCR0 or (XCRO | IA32_XSS)
needs to be updated.
Fixes: a554d207dc46 ("KVM: X86: Processor States following Reset or INIT")
Signed-off-by: Like Xu <likexu@xxxxxxxxxxx>
Can you write a test case please?
Thanks,
Paolo
---
arch/x86/kvm/x86.c | 8 ++++++++
1 file changed, 8 insertions(+)
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 76b4803dd3bd..5748a57e1cb7 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -11134,6 +11134,7 @@ void kvm_vcpu_reset(struct kvm_vcpu *vcpu, bool init_event)
struct kvm_cpuid_entry2 *cpuid_0x1;
unsigned long old_cr0 = kvm_read_cr0(vcpu);
unsigned long new_cr0;
+ bool need_update_cpuid = false;
/*
* Several of the "set" flows, e.g. ->set_cr0(), read other registers
@@ -11199,6 +11200,8 @@ void kvm_vcpu_reset(struct kvm_vcpu *vcpu, bool init_event)
vcpu->arch.msr_misc_features_enables = 0;
+ if (vcpu->arch.xcr0 != XFEATURE_MASK_FP)
+ need_update_cpuid = true;
vcpu->arch.xcr0 = XFEATURE_MASK_FP;
}
@@ -11216,6 +11219,8 @@ void kvm_vcpu_reset(struct kvm_vcpu *vcpu, bool init_event)
cpuid_0x1 = kvm_find_cpuid_entry(vcpu, 1, 0);
kvm_rdx_write(vcpu, cpuid_0x1 ? cpuid_0x1->eax : 0x600);
+ if (vcpu->arch.ia32_xss)
+ need_update_cpuid = true;
vcpu->arch.ia32_xss = 0;
static_call(kvm_x86_vcpu_reset)(vcpu, init_event);
@@ -11264,6 +11269,9 @@ void kvm_vcpu_reset(struct kvm_vcpu *vcpu, bool init_event)
*/
if (init_event)
kvm_make_request(KVM_REQ_TLB_FLUSH_GUEST, vcpu);
+
+ if (need_update_cpuid)
+ kvm_update_cpuid_runtime(vcpu);
}
EXPORT_SYMBOL_GPL(kvm_vcpu_reset);
