KVM: SVM: Load %gs earlier if CONFIG_X86_32_LAZY_GS=n

With CONFIG_CC_STACKPROTECTOR, we need a valid %gs at all times, so disable
lazy reload and do an eager reload immediately after the vmexit.

Reported-by: IVAN ANGELOV <ivangotoy@gmail.com>
Acked-By: Joerg Roedel <joerg.roedel@amd.com>
Signed-off-by: Avi Kivity <avi@redhat.com>

1 files changed, 5 insertions, 0 deletions

diff --git a/arch/x86/kvm/svm.c b/arch/x86/kvm/svm.c
index 8d61df4a02c7..6bb15d583e47 100644
--- a/arch/x86/kvm/svm.c
+++ b/arch/x86/kvm/svm.c
@@ -1155,8 +1155,10 @@ static void svm_vcpu_put(struct kvm_vcpu *vcpu)
         wrmsrl(MSR_KERNEL_GS_BASE, current->thread.gs);
         load_gs_index(svm->host.gs);
 #else
+#ifdef CONFIG_X86_32_LAZY_GS
         loadsegment(gs, svm->host.gs);
 #endif
+#endif
         for (i = 0; i < NR_HOST_SAVE_USER_MSRS; i++)
                 wrmsrl(host_save_user_msrs[i], svm->host_user_msrs[i]);
 }
@@ -3649,6 +3651,9 @@ static void svm_vcpu_run(struct kvm_vcpu *vcpu)
         wrmsrl(MSR_GS_BASE, svm->host.gs_base);
 #else
         loadsegment(fs, svm->host.fs);
+#ifndef CONFIG_X86_32_LAZY_GS
+        loadsegment(gs, svm->host.gs);
+#endif
 #endif
 
         reload_tss(vcpu);