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authorTom Lendacky <thomas.lendacky@amd.com>2021-05-06 23:14:41 +0300
committerPaolo Bonzini <pbonzini@redhat.com>2021-05-07 13:06:23 +0300
commitce7ea0cfdc2e9ff31d12da31c3226deddb9644f5 (patch)
tree921b38c2bc256a037a897cdb62889aeab8f3fd4f /arch
parent368340a3c7d9a207bfe544721d464b7109be8eae (diff)
downloadlinux-ce7ea0cfdc2e9ff31d12da31c3226deddb9644f5.tar.xz
KVM: SVM: Move GHCB unmapping to fix RCU warning
When an SEV-ES guest is running, the GHCB is unmapped as part of the vCPU run support. However, kvm_vcpu_unmap() triggers an RCU dereference warning with CONFIG_PROVE_LOCKING=y because the SRCU lock is released before invoking the vCPU run support. Move the GHCB unmapping into the prepare_guest_switch callback, which is invoked while still holding the SRCU lock, eliminating the RCU dereference warning. Fixes: 291bd20d5d88 ("KVM: SVM: Add initial support for a VMGEXIT VMEXIT") Reported-by: Borislav Petkov <bp@alien8.de> Signed-off-by: Tom Lendacky <thomas.lendacky@amd.com> Message-Id: <b2f9b79d15166f2c3e4375c0d9bc3268b7696455.1620332081.git.thomas.lendacky@amd.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Diffstat (limited to 'arch')
-rw-r--r--arch/x86/kvm/svm/sev.c5
-rw-r--r--arch/x86/kvm/svm/svm.c3
-rw-r--r--arch/x86/kvm/svm/svm.h1
3 files changed, 5 insertions, 4 deletions
diff --git a/arch/x86/kvm/svm/sev.c b/arch/x86/kvm/svm/sev.c
index eb241c1a4add..5bc887e9a986 100644
--- a/arch/x86/kvm/svm/sev.c
+++ b/arch/x86/kvm/svm/sev.c
@@ -2197,7 +2197,7 @@ vmgexit_err:
return -EINVAL;
}
-static void pre_sev_es_run(struct vcpu_svm *svm)
+void sev_es_unmap_ghcb(struct vcpu_svm *svm)
{
if (!svm->ghcb)
return;
@@ -2233,9 +2233,6 @@ void pre_sev_run(struct vcpu_svm *svm, int cpu)
struct svm_cpu_data *sd = per_cpu(svm_data, cpu);
int asid = sev_get_asid(svm->vcpu.kvm);
- /* Perform any SEV-ES pre-run actions */
- pre_sev_es_run(svm);
-
/* Assign the asid allocated with this SEV guest */
svm->asid = asid;
diff --git a/arch/x86/kvm/svm/svm.c b/arch/x86/kvm/svm/svm.c
index 8124f51e9488..4dd9b7856e5b 100644
--- a/arch/x86/kvm/svm/svm.c
+++ b/arch/x86/kvm/svm/svm.c
@@ -1437,6 +1437,9 @@ static void svm_prepare_guest_switch(struct kvm_vcpu *vcpu)
struct vcpu_svm *svm = to_svm(vcpu);
struct svm_cpu_data *sd = per_cpu(svm_data, vcpu->cpu);
+ if (sev_es_guest(vcpu->kvm))
+ sev_es_unmap_ghcb(svm);
+
if (svm->guest_state_loaded)
return;
diff --git a/arch/x86/kvm/svm/svm.h b/arch/x86/kvm/svm/svm.h
index 84b3133c2251..e44567ceb865 100644
--- a/arch/x86/kvm/svm/svm.h
+++ b/arch/x86/kvm/svm/svm.h
@@ -581,6 +581,7 @@ void sev_es_init_vmcb(struct vcpu_svm *svm);
void sev_es_create_vcpu(struct vcpu_svm *svm);
void sev_vcpu_deliver_sipi_vector(struct kvm_vcpu *vcpu, u8 vector);
void sev_es_prepare_guest_switch(struct vcpu_svm *svm, unsigned int cpu);
+void sev_es_unmap_ghcb(struct vcpu_svm *svm);
/* vmenter.S */