[PATCH 11/19] kvm: x86: Check fpstate reallocation in XSETBV emulation

Yang Zhong
2021-12-07T15:10:01Z

XSETBV allows the software to write the extended control register
XCR0, thus its emulation handler also needs to check fpstate
reallocation when the changed XCR0 value enables certain
dynamically-enabled features.

Signed-off-by: Jing Liu <jing2.liu@intel.com>
Signed-off-by: Yang Zhong <yang.zhong@intel.com>
---
arch/x86/kvm/x86.c | 9 +++++++++
1 file changed, 9 insertions(+)

diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index c83887cb55ee..b195f4fa888f 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -1028,6 +1028,15 @@ int kvm_emulate_xsetbv(struct kvm_vcpu *vcpu)
return 1;
}

+ if (guest_cpuid_has(vcpu, X86_FEATURE_XFD)) {
+ if (kvm_check_guest_realloc_fpstate(vcpu, vcpu->arch.guest_fpu.fpstate->xfd)) {
+ vcpu->run->exit_reason = KVM_EXIT_FPU_REALLOC;
+ vcpu->arch.complete_userspace_io =
+ kvm_skip_emulated_instruction;
+ return 0;
+ }
+ }
+
return kvm_skip_emulated_instruction(vcpu);
}
EXPORT_SYMBOL_GPL(kvm_emulate_xsetbv);