[PATCH 5.18 103/181] KVM: SEV: Init target VMCBs in sev_migrate_from

From: Greg Kroah-Hartman
Date: Mon Jun 27 2022 - 07:55:38 EST


From: Peter Gonda <pgonda@xxxxxxxxxx>

[ Upstream commit 6defa24d3b12bbd418bc8526dea1cbc605265c06 ]

The target VMCBs during an intra-host migration need to correctly setup
for running SEV and SEV-ES guests. Add sev_init_vmcb() function and make
sev_es_init_vmcb() static. sev_init_vmcb() uses the now private function
to init SEV-ES guests VMCBs when needed.

Fixes: 0b020f5af092 ("KVM: SEV: Add support for SEV-ES intra host migration")
Fixes: b56639318bb2 ("KVM: SEV: Add support for SEV intra host migration")
Signed-off-by: Peter Gonda <pgonda@xxxxxxxxxx>
Cc: Marc Orr <marcorr@xxxxxxxxxx>
Cc: Paolo Bonzini <pbonzini@xxxxxxxxxx>
Cc: Sean Christopherson <seanjc@xxxxxxxxxx>
Cc: Tom Lendacky <thomas.lendacky@xxxxxxx>
Cc: kvm@xxxxxxxxxxxxxxx
Cc: linux-kernel@xxxxxxxxxxxxxxx
Message-Id: <20220623173406.744645-1-pgonda@xxxxxxxxxx>
Signed-off-by: Paolo Bonzini <pbonzini@xxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
arch/x86/kvm/svm/sev.c | 68 ++++++++++++++++++++++++++++--------------
arch/x86/kvm/svm/svm.c | 11 ++-----
arch/x86/kvm/svm/svm.h | 2 +-
3 files changed, 48 insertions(+), 33 deletions(-)

diff --git a/arch/x86/kvm/svm/sev.c b/arch/x86/kvm/svm/sev.c
index 4b7d490c0b63..76e9e6eb71d6 100644
--- a/arch/x86/kvm/svm/sev.c
+++ b/arch/x86/kvm/svm/sev.c
@@ -1665,19 +1665,24 @@ static void sev_migrate_from(struct kvm *dst_kvm, struct kvm *src_kvm)
{
struct kvm_sev_info *dst = &to_kvm_svm(dst_kvm)->sev_info;
struct kvm_sev_info *src = &to_kvm_svm(src_kvm)->sev_info;
+ struct kvm_vcpu *dst_vcpu, *src_vcpu;
+ struct vcpu_svm *dst_svm, *src_svm;
struct kvm_sev_info *mirror;
+ unsigned long i;

dst->active = true;
dst->asid = src->asid;
dst->handle = src->handle;
dst->pages_locked = src->pages_locked;
dst->enc_context_owner = src->enc_context_owner;
+ dst->es_active = src->es_active;

src->asid = 0;
src->active = false;
src->handle = 0;
src->pages_locked = 0;
src->enc_context_owner = NULL;
+ src->es_active = false;

list_cut_before(&dst->regions_list, &src->regions_list, &src->regions_list);

@@ -1704,26 +1709,21 @@ static void sev_migrate_from(struct kvm *dst_kvm, struct kvm *src_kvm)
list_del(&src->mirror_entry);
list_add_tail(&dst->mirror_entry, &owner_sev_info->mirror_vms);
}
-}

-static int sev_es_migrate_from(struct kvm *dst, struct kvm *src)
-{
- unsigned long i;
- struct kvm_vcpu *dst_vcpu, *src_vcpu;
- struct vcpu_svm *dst_svm, *src_svm;
+ kvm_for_each_vcpu(i, dst_vcpu, dst_kvm) {
+ dst_svm = to_svm(dst_vcpu);

- if (atomic_read(&src->online_vcpus) != atomic_read(&dst->online_vcpus))
- return -EINVAL;
+ sev_init_vmcb(dst_svm);

- kvm_for_each_vcpu(i, src_vcpu, src) {
- if (!src_vcpu->arch.guest_state_protected)
- return -EINVAL;
- }
+ if (!dst->es_active)
+ continue;

- kvm_for_each_vcpu(i, src_vcpu, src) {
+ /*
+ * Note, the source is not required to have the same number of
+ * vCPUs as the destination when migrating a vanilla SEV VM.
+ */
+ src_vcpu = kvm_get_vcpu(dst_kvm, i);
src_svm = to_svm(src_vcpu);
- dst_vcpu = kvm_get_vcpu(dst, i);
- dst_svm = to_svm(dst_vcpu);

/*
* Transfer VMSA and GHCB state to the destination. Nullify and
@@ -1740,8 +1740,23 @@ static int sev_es_migrate_from(struct kvm *dst, struct kvm *src)
src_svm->vmcb->control.vmsa_pa = INVALID_PAGE;
src_vcpu->arch.guest_state_protected = false;
}
- to_kvm_svm(src)->sev_info.es_active = false;
- to_kvm_svm(dst)->sev_info.es_active = true;
+}
+
+static int sev_check_source_vcpus(struct kvm *dst, struct kvm *src)
+{
+ struct kvm_vcpu *src_vcpu;
+ unsigned long i;
+
+ if (!sev_es_guest(src))
+ return 0;
+
+ if (atomic_read(&src->online_vcpus) != atomic_read(&dst->online_vcpus))
+ return -EINVAL;
+
+ kvm_for_each_vcpu(i, src_vcpu, src) {
+ if (!src_vcpu->arch.guest_state_protected)
+ return -EINVAL;
+ }

return 0;
}
@@ -1789,11 +1804,9 @@ int sev_vm_move_enc_context_from(struct kvm *kvm, unsigned int source_fd)
if (ret)
goto out_dst_vcpu;

- if (sev_es_guest(source_kvm)) {
- ret = sev_es_migrate_from(kvm, source_kvm);
- if (ret)
- goto out_source_vcpu;
- }
+ ret = sev_check_source_vcpus(kvm, source_kvm);
+ if (ret)
+ goto out_source_vcpu;

sev_migrate_from(kvm, source_kvm);
kvm_vm_dead(source_kvm);
@@ -2910,7 +2923,7 @@ int sev_es_string_io(struct vcpu_svm *svm, int size, unsigned int port, int in)
count, in);
}

-void sev_es_init_vmcb(struct vcpu_svm *svm)
+static void sev_es_init_vmcb(struct vcpu_svm *svm)
{
struct kvm_vcpu *vcpu = &svm->vcpu;

@@ -2955,6 +2968,15 @@ void sev_es_init_vmcb(struct vcpu_svm *svm)
set_msr_interception(vcpu, svm->msrpm, MSR_IA32_LASTINTTOIP, 1, 1);
}

+void sev_init_vmcb(struct vcpu_svm *svm)
+{
+ svm->vmcb->control.nested_ctl |= SVM_NESTED_CTL_SEV_ENABLE;
+ clr_exception_intercept(svm, UD_VECTOR);
+
+ if (sev_es_guest(svm->vcpu.kvm))
+ sev_es_init_vmcb(svm);
+}
+
void sev_es_vcpu_reset(struct vcpu_svm *svm)
{
/*
diff --git a/arch/x86/kvm/svm/svm.c b/arch/x86/kvm/svm/svm.c
index 0c0a09b43b10..6bfb0b0e66bd 100644
--- a/arch/x86/kvm/svm/svm.c
+++ b/arch/x86/kvm/svm/svm.c
@@ -1125,15 +1125,8 @@ static void init_vmcb(struct kvm_vcpu *vcpu)
svm->vmcb->control.int_ctl |= V_GIF_ENABLE_MASK;
}

- if (sev_guest(vcpu->kvm)) {
- svm->vmcb->control.nested_ctl |= SVM_NESTED_CTL_SEV_ENABLE;
- clr_exception_intercept(svm, UD_VECTOR);
-
- if (sev_es_guest(vcpu->kvm)) {
- /* Perform SEV-ES specific VMCB updates */
- sev_es_init_vmcb(svm);
- }
- }
+ if (sev_guest(vcpu->kvm))
+ sev_init_vmcb(svm);

svm_hv_init_vmcb(svm->vmcb);
init_vmcb_after_set_cpuid(vcpu);
diff --git a/arch/x86/kvm/svm/svm.h b/arch/x86/kvm/svm/svm.h
index 34babf9185fe..8ec8fb58b924 100644
--- a/arch/x86/kvm/svm/svm.h
+++ b/arch/x86/kvm/svm/svm.h
@@ -616,10 +616,10 @@ void __init sev_set_cpu_caps(void);
void __init sev_hardware_setup(void);
void sev_hardware_unsetup(void);
int sev_cpu_init(struct svm_cpu_data *sd);
+void sev_init_vmcb(struct vcpu_svm *svm);
void sev_free_vcpu(struct kvm_vcpu *vcpu);
int sev_handle_vmgexit(struct kvm_vcpu *vcpu);
int sev_es_string_io(struct vcpu_svm *svm, int size, unsigned int port, int in);
-void sev_es_init_vmcb(struct vcpu_svm *svm);
void sev_es_vcpu_reset(struct vcpu_svm *svm);
void sev_vcpu_deliver_sipi_vector(struct kvm_vcpu *vcpu, u8 vector);
void sev_es_prepare_switch_to_guest(struct vmcb_save_area *hostsa);
--
2.35.1