Several hypervisors need MSR auto load/restore feature.
We read MSRs from VM-entry MSR load area which specified by L1,
and load them via kvm_set_msr in the nested entry.
When nested exit occurs, we get MSRs via kvm_get_msr, writing
them to L1`s MSR store area. After this, we read MSRs from VM-exit
MSR load area, and load them via kvm_set_msr.
Signed-off-by: Wincy Van <fanwenyi0529@xxxxxxxxx>
---
arch/x86/include/uapi/asm/vmx.h | 5 +++
arch/x86/kvm/vmx.c | 68 +++++++++++++++++++++++++++++++++++++++++
arch/x86/kvm/x86.c | 1 +
virt/kvm/kvm_main.c | 1 +
4 files changed, 75 insertions(+)
diff --git a/arch/x86/include/uapi/asm/vmx.h b/arch/x86/include/uapi/asm/vmx.h
index b813bf9..ff2b8e2 100644
--- a/arch/x86/include/uapi/asm/vmx.h
+++ b/arch/x86/include/uapi/asm/vmx.h
@@ -56,6 +56,7 @@
#define EXIT_REASON_MSR_READ 31
#define EXIT_REASON_MSR_WRITE 32
#define EXIT_REASON_INVALID_STATE 33
+#define EXIT_REASON_MSR_LOAD_FAIL 34
#define EXIT_REASON_MWAIT_INSTRUCTION 36
#define EXIT_REASON_MONITOR_INSTRUCTION 39
#define EXIT_REASON_PAUSE_INSTRUCTION 40
@@ -116,10 +117,14 @@
{ EXIT_REASON_APIC_WRITE, "APIC_WRITE" }, \
{ EXIT_REASON_EOI_INDUCED, "EOI_INDUCED" }, \
{ EXIT_REASON_INVALID_STATE, "INVALID_STATE" }, \
+ { EXIT_REASON_MSR_LOAD_FAIL, "MSR_LOAD_FAIL" }, \
{ EXIT_REASON_INVD, "INVD" }, \
{ EXIT_REASON_INVVPID, "INVVPID" }, \
{ EXIT_REASON_INVPCID, "INVPCID" }, \
{ EXIT_REASON_XSAVES, "XSAVES" }, \
{ EXIT_REASON_XRSTORS, "XRSTORS" }
+#define VMX_ABORT_SAVE_GUEST_MSR_FAIL 1
+#define VMX_ABORT_LOAD_HOST_MSR_FAIL 4
+
#endif /* _UAPIVMX_H */
diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
index 9bcc871..b49d198 100644
--- a/arch/x86/kvm/vmx.c
+++ b/arch/x86/kvm/vmx.c
@@ -6143,6 +6143,13 @@ static void nested_vmx_failValid(struct kvm_vcpu *vcpu,
*/
}
+static void nested_vmx_abort(struct kvm_vcpu *vcpu, u32 indicator)
+{
+ /* TODO: not to reset guest simply here. */
+ kvm_make_request(KVM_REQ_TRIPLE_FAULT, vcpu);
+ pr_warn("kvm: nested vmx abort, indicator %d\n", indicator);
+}
+
static enum hrtimer_restart vmx_preemption_timer_fn(struct hrtimer *timer)
{
struct vcpu_vmx *vmx =
@@ -8286,6 +8293,67 @@ static void vmx_start_preemption_timer(struct kvm_vcpu *vcpu)
ns_to_ktime(preemption_timeout), HRTIMER_MODE_REL);
}
+static inline int nested_vmx_msr_check_common(struct vmx_msr_entry *e)
+{
+ if (e->index >> 8 == 0x8 || e->reserved != 0)
+ return -EINVAL;
+ return 0;
+}
+
+static inline int nested_vmx_load_msr_check(struct vmx_msr_entry *e)
+{
+ if (e->index == MSR_FS_BASE ||
+ e->index == MSR_GS_BASE ||
+ nested_vmx_msr_check_common(e))
+ return -EINVAL;
+ return 0;
+}
+
+/*
+ * Load guest's/host's msr at nested entry/exit.
+ * return 0 for success, entry index for failure.
+ */
+static u32 nested_vmx_load_msr(struct kvm_vcpu *vcpu, u64 gpa, u32 count)
+{
+ u32 i;
+ struct vmx_msr_entry e;
+ struct msr_data msr;
+
+ msr.host_initiated = false;
+ for (i = 0; i < count; i++) {
+ kvm_read_guest(vcpu->kvm, gpa + i * sizeof(e), &e, sizeof(e));
+ if (nested_vmx_load_msr_check(&e))
+ goto fail;
+ msr.index = e.index;
+ msr.data = e.value;
+ if (kvm_set_msr(vcpu, &msr))
+ goto fail;
+ }
+ return 0;
+fail:
+ return i + 1;
+}
+
+static int nested_vmx_store_msr(struct kvm_vcpu *vcpu, u64 gpa, u32 count)
+{
+ u32 i;
+ struct vmx_msr_entry e;
+
+ for (i = 0; i < count; i++) {
+ kvm_read_guest(vcpu->kvm, gpa + i * sizeof(e),
+ &e, 2 * sizeof(u32));
+ if (nested_vmx_msr_check_common(&e))
+ return -EINVAL;
+ if (kvm_get_msr(vcpu, e.index, &e.value))
+ return -EINVAL;
+ kvm_write_guest(vcpu->kvm,
+ gpa + i * sizeof(e) +
+ offsetof(struct vmx_msr_entry, value),
+ &e.value, sizeof(e.value));
+ }
+ return 0;
+}
+
/*
* prepare_vmcs02 is called when the L1 guest hypervisor runs its nested
* L2 guest. L1 has a vmcs for L2 (vmcs12), and this function "merges" it
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index c259814..af9faed 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -2324,6 +2324,7 @@ int kvm_get_msr(struct kvm_vcpu *vcpu, u32 msr_index, u64 *pdata)
{
return kvm_x86_ops->get_msr(vcpu, msr_index, pdata);
}
+EXPORT_SYMBOL_GPL(kvm_get_msr);
static int get_msr_mtrr(struct kvm_vcpu *vcpu, u32 msr, u64 *pdata)
{
diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
index c5c186a..77179c5 100644
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -1579,6 +1579,7 @@ int kvm_write_guest(struct kvm *kvm, gpa_t gpa, const void *data,
}
return 0;
}
+EXPORT_SYMBOL_GPL(kvm_write_guest);
int kvm_gfn_to_hva_cache_init(struct kvm *kvm, struct gfn_to_hva_cache *ghc,
gpa_t gpa, unsigned long len)
--
2.0.4
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