From: Isaku Yamahata <isaku.yamahata@xxxxxxxxx>
On exiting from the guest TD, xsave state is clobbered; restore it.
Signed-off-by: Isaku Yamahata <isaku.yamahata@xxxxxxxxx>
Signed-off-by: Adrian Hunter <adrian.hunter@xxxxxxxxx>
Message-ID: <20250129095902.16391-8-adrian.hunter@xxxxxxxxx>
[Rewrite to not use kvm_load_host_xsave_state. - Paolo]
Signed-off-by: Paolo Bonzini <pbonzini@xxxxxxxxxx>
---
arch/x86/kvm/vmx/tdx.c | 32 ++++++++++++++++++++++++++++++++
1 file changed, 32 insertions(+)
diff --git a/arch/x86/kvm/vmx/tdx.c b/arch/x86/kvm/vmx/tdx.c
index 94e08fdcb775..b2948318cd8b 100644
--- a/arch/x86/kvm/vmx/tdx.c
+++ b/arch/x86/kvm/vmx/tdx.c
@@ -2,6 +2,7 @@
#include <linux/cleanup.h>
#include <linux/cpu.h>
#include <asm/cpufeature.h>
+#include <asm/fpu/xcr.h>
#include <linux/misc_cgroup.h>
#include <linux/mmu_context.h>
#include <asm/tdx.h>
@@ -735,6 +736,30 @@ static noinstr void tdx_vcpu_enter_exit(struct kvm_vcpu *vcpu)
BIT_ULL(VCPU_REGS_R14) | \
BIT_ULL(VCPU_REGS_R15))
+static void tdx_load_host_xsave_state(struct kvm_vcpu *vcpu)
+{
+ struct kvm_tdx *kvm_tdx = to_kvm_tdx(vcpu->kvm);
+
+ /*
+ * All TDX hosts support PKRU; but even if they didn't,
+ * vcpu->arch.host_pkru would be 0 and the wrpkru would be
+ * skipped.
+ */
+ if (vcpu->arch.host_pkru != 0)
+ wrpkru(vcpu->arch.host_pkru);
+
+ if (kvm_host.xcr0 != (kvm_tdx->xfam & kvm_caps.supported_xcr0))
+ xsetbv(XCR_XFEATURE_ENABLED_MASK, kvm_host.xcr0);
+
+ /*
+ * Likewise, even if a TDX hosts didn't support XSS both arms of
+ * the comparison would be 0 and the wrmsrl would be skipped.
+ */
+ if (kvm_host.xss != (kvm_tdx->xfam & kvm_caps.supported_xss))
+ wrmsrl(MSR_IA32_XSS, kvm_host.xss);
+}
+EXPORT_SYMBOL_GPL(kvm_load_host_xsave_state);
+
fastpath_t tdx_vcpu_run(struct kvm_vcpu *vcpu, bool force_immediate_exit)
{
/*
@@ -751,6 +776,8 @@ fastpath_t tdx_vcpu_run(struct kvm_vcpu *vcpu, bool force_immediate_exit)
tdx_vcpu_enter_exit(vcpu);
+ tdx_load_host_xsave_state(vcpu);
+
vcpu->arch.regs_avail &= TDX_REGS_AVAIL_SET;
trace_kvm_exit(vcpu, KVM_ISA_VMX);
@@ -2326,6 +2353,11 @@ int __init tdx_bringup(void)
goto success_disable_tdx;
}
+ if (!cpu_feature_enabled(X86_FEATURE_OSXSAVE)) {
+ pr_err("tdx: OSXSAVE is required for TDX\n");
+ goto success_disable_tdx;
+ }
+
if (!cpu_feature_enabled(X86_FEATURE_MOVDIR64B)) {
pr_err("tdx: MOVDIR64B is required for TDX\n");
goto success_disable_tdx;
--
2.43.5
