SEV hardware uses ASIDs to associate a memory encryption key with a
guest VM. During guest creation, a SEV VM uses the SEV_CMD_ACTIVATE
command to bind a particular ASID to the guest. Lets make sure that the
VMCB is programmed with the bound ASID before a VMRUN.
Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Cc: Ingo Molnar <mingo@xxxxxxxxxx>
Cc: "H. Peter Anvin" <hpa@xxxxxxxxx>
Cc: Paolo Bonzini <pbonzini@xxxxxxxxxx>
Cc: "Radim Krčmář" <rkrcmar@xxxxxxxxxx>
Cc: Joerg Roedel <joro@xxxxxxxxxx>
Cc: Borislav Petkov <bp@xxxxxxx>
Cc: Tom Lendacky <thomas.lendacky@xxxxxxx>
Cc: x86@xxxxxxxxxx
Cc: kvm@xxxxxxxxxxxxxxx
Cc: linux-kernel@xxxxxxxxxxxxxxx
Signed-off-by: Brijesh Singh <brijesh.singh@xxxxxxx>
Reviewed-by: Borislav Petkov <bp@xxxxxxx>
---
arch/x86/kvm/svm.c | 58 ++++++++++++++++++++++++++++++++++++++++++++++++++++--
1 file changed, 56 insertions(+), 2 deletions(-)
diff --git a/arch/x86/kvm/svm.c b/arch/x86/kvm/svm.c
index 7379fc218128..9d04cc8fbbf9 100644
--- a/arch/x86/kvm/svm.c
+++ b/arch/x86/kvm/svm.c
@@ -213,6 +213,9 @@ struct vcpu_svm {
*/
struct list_head ir_list;
spinlock_t ir_list_lock;
+
+ /* which host CPU was used for running this vcpu */
+ unsigned int last_cpu;
};
/*
@@ -340,6 +343,13 @@ static inline bool sev_guest(struct kvm *kvm)
return sev->active;
}
+static inline int sev_get_asid(struct kvm *kvm)
+{
+ struct kvm_sev_info *sev = &kvm->arch.sev_info;
+
+ return sev->asid;
+}
+
static inline void mark_all_dirty(struct vmcb *vmcb)
{
vmcb->control.clean = 0;
@@ -550,6 +560,9 @@ struct svm_cpu_data {
struct kvm_ldttss_desc *tss_desc;
struct page *save_area;
+
+ /* index = sev_asid, value = vmcb pointer */
+ struct vmcb **sev_vmcbs;
};
static DEFINE_PER_CPU(struct svm_cpu_data *, svm_data);
@@ -863,6 +876,7 @@ static void svm_cpu_uninit(int cpu)
return;
per_cpu(svm_data, raw_smp_processor_id()) = NULL;
+ kfree(sd->sev_vmcbs);
__free_page(sd->save_area);
kfree(sd);
}
@@ -876,11 +890,18 @@ static int svm_cpu_init(int cpu)
if (!sd)
return -ENOMEM;
sd->cpu = cpu;
- sd->save_area = alloc_page(GFP_KERNEL);
r = -ENOMEM;
+ sd->save_area = alloc_page(GFP_KERNEL);
if (!sd->save_area)
goto err_1;
+ if (svm_sev_enabled()) {
+ r = -ENOMEM;
+ sd->sev_vmcbs = kmalloc((max_sev_asid + 1) * sizeof(void *), GFP_KERNEL);
+ if (!sd->sev_vmcbs)
+ goto err_1;
+ }
+
per_cpu(svm_data, cpu) = sd;
return 0;
@@ -1468,10 +1489,16 @@ static int avic_init_backing_page(struct kvm_vcpu *vcpu)
static void __sev_asid_free(int asid)
{
- int pos;
+ struct svm_cpu_data *sd;
+ int cpu, pos;
pos = asid - 1;
clear_bit(pos, sev_asid_bitmap);
+
+ for_each_possible_cpu(cpu) {
+ sd = per_cpu(svm_data, cpu);
+ sd->sev_vmcbs[pos] = NULL;
+ }
}
static void sev_asid_free(struct kvm *kvm)
@@ -4429,12 +4456,39 @@ static void reload_tss(struct kvm_vcpu *vcpu)
load_TR_desc();
}
+static 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);
+
+ /* Assign the asid allocated with this SEV guest */
+ svm->vmcb->control.asid = asid;
+
+ /*
+ * Flush guest TLB:
+ *
+ * 1) when different VMCB for the same ASID is to be run on the same host CPU.
+ * 2) or this VMCB was executed on different host CPU in previous VMRUNs.
+ */
+ if (sd->sev_vmcbs[asid] == svm->vmcb &&
+ svm->last_cpu == cpu)
+ return;
+
+ svm->last_cpu = cpu;
+ sd->sev_vmcbs[asid] = svm->vmcb;
+ svm->vmcb->control.tlb_ctl = TLB_CONTROL_FLUSH_ASID;
+ mark_dirty(svm->vmcb, VMCB_ASID);
+}
+
static void pre_svm_run(struct vcpu_svm *svm)
{
int cpu = raw_smp_processor_id();
struct svm_cpu_data *sd = per_cpu(svm_data, cpu);
+ if (sev_guest(svm->vcpu.kvm))
+ return pre_sev_run(svm, cpu);
+
/* FIXME: handle wraparound of asid_generation */
if (svm->asid_generation != sd->asid_generation)
new_asid(svm, sd);
--
2.9.5
