Re: [RFC PATCH v5 071/104] KVM: TDX: restore debug store when TD exit

From: Paolo Bonzini
Date: Fri Apr 15 2022 - 10:22:28 EST


On 3/4/22 20:49, isaku.yamahata@xxxxxxxxx wrote:
From: Isaku Yamahata <isaku.yamahata@xxxxxxxxx>

Because debug store is clobbered, restore it on TD exit.

Signed-off-by: Isaku Yamahata <isaku.yamahata@xxxxxxxxx>
---
arch/x86/events/intel/ds.c | 1 +
arch/x86/kvm/vmx/tdx.c | 1 +
2 files changed, 2 insertions(+)

diff --git a/arch/x86/events/intel/ds.c b/arch/x86/events/intel/ds.c
index 376cc3d66094..cdba4227ad3b 100644
--- a/arch/x86/events/intel/ds.c
+++ b/arch/x86/events/intel/ds.c
@@ -2256,3 +2256,4 @@ void perf_restore_debug_store(void)
wrmsrl(MSR_IA32_DS_AREA, (unsigned long)ds);
}
+EXPORT_SYMBOL_GPL(perf_restore_debug_store);
diff --git a/arch/x86/kvm/vmx/tdx.c b/arch/x86/kvm/vmx/tdx.c
index 3cb2fbd1c12c..37cf7d43435d 100644
--- a/arch/x86/kvm/vmx/tdx.c
+++ b/arch/x86/kvm/vmx/tdx.c
@@ -620,6 +620,7 @@ fastpath_t tdx_vcpu_run(struct kvm_vcpu *vcpu)
tdx_vcpu_enter_exit(vcpu, tdx);
tdx_user_return_update_cache();
+ perf_restore_debug_store();
tdx_restore_host_xsave_state(vcpu);
tdx->host_state_need_restore = true;

Reviewed-by: Paolo Bonzini <pbonzini@xxxxxxxxxx>