This patch improve checks required by Intel Software Developer Manual.
- SMM MSRs are not allowed.
- microcode MSRs are not allowed.
- check x2apic MSRs only when LAPIC is in x2apic mode.
- MSR switch areas must be aligned to 16 bytes.
- address of first and last byte in MSR switch areas should not set any bits
beyond the processor's physical-address width.
Also it adds warning messages on failures during MSR switch. These messages
are useful for people who debug their VMMs in nVMX.
Signed-off-by: Eugene Korenevsky <ekorenevsky@xxxxxxxxx>
---
arch/x86/include/uapi/asm/msr-index.h | 3 +
arch/x86/kvm/vmx.c | 123 ++++++++++++++++++++++++++++++----
2 files changed, 112 insertions(+), 14 deletions(-)
diff --git a/arch/x86/include/uapi/asm/msr-index.h b/arch/x86/include/uapi/asm/msr-index.h
index e21331c..3c9c601 100644
--- a/arch/x86/include/uapi/asm/msr-index.h
+++ b/arch/x86/include/uapi/asm/msr-index.h
@@ -316,6 +316,9 @@
#define MSR_IA32_UCODE_WRITE 0x00000079
#define MSR_IA32_UCODE_REV 0x0000008b
+#define MSR_IA32_SMM_MONITOR_CTL 0x0000009b
+#define MSR_IA32_SMBASE 0x0000009e
+
#define MSR_IA32_PERF_STATUS 0x00000198
#define MSR_IA32_PERF_CTL 0x00000199
#define MSR_AMD_PSTATE_DEF_BASE 0xc0010064
diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
index b49d198..ac1fa1c2 100644
--- a/arch/x86/kvm/vmx.c
+++ b/arch/x86/kvm/vmx.c
@@ -8293,18 +8293,80 @@ 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)
+static int nested_vmx_check_msr_switch(struct kvm_vcpu *vcpu,
+ unsigned long count_field,
+ unsigned long addr_field,
+ int maxphyaddr)
{
- if (e->index >> 8 == 0x8 || e->reserved != 0)
+ u64 count, addr;
+
+ if (vmcs12_read_any(vcpu, count_field, &count) ||
+ vmcs12_read_any(vcpu, addr_field, &addr)) {
+ WARN_ON(1);
+ return -EINVAL;
+ }
+ if (count == 0)
+ return 0;
+ if (!IS_ALIGNED(addr, 16) || addr >> maxphyaddr ||
+ (addr + count * sizeof(struct vmx_msr_entry) - 1) >> maxphyaddr) {
+ pr_warn_ratelimited(
+ "nVMX: invalid MSR switch (0x%lx, %d, %llu, 0x%08llx)",
+ addr_field, maxphyaddr, count, addr);
+ return -EINVAL;
+ }
+ return 0;
+}
+
+static int nested_vmx_check_msr_switch_controls(struct kvm_vcpu *vcpu,
+ struct vmcs12 *vmcs12)
+{
+ int maxphyaddr;
+
+ if (vmcs12->vm_exit_msr_load_count == 0 &&
+ vmcs12->vm_exit_msr_store_count == 0 &&
+ vmcs12->vm_entry_msr_load_count == 0)
+ return 0; /* Fast path */
+ maxphyaddr = cpuid_maxphyaddr(vcpu);
+ if (nested_vmx_check_msr_switch(vcpu, VM_EXIT_MSR_LOAD_COUNT,
+ VM_EXIT_MSR_LOAD_ADDR, maxphyaddr) ||
+ nested_vmx_check_msr_switch(vcpu, VM_EXIT_MSR_STORE_COUNT,
+ VM_EXIT_MSR_STORE_ADDR, maxphyaddr) ||
+ nested_vmx_check_msr_switch(vcpu, VM_ENTRY_MSR_LOAD_COUNT,
+ VM_ENTRY_MSR_LOAD_ADDR, maxphyaddr))
+ return -EINVAL;
+ return 0;
+}
+
+static int nested_vmx_msr_check_common(struct kvm_vcpu *vcpu,
+ struct vmx_msr_entry *e)
+{
+ /* x2APIC MSR accesses are not allowed */
+ if (apic_x2apic_mode(vcpu->arch.apic) && e->index >> 8 == 0x8)
+ return -EINVAL;
+ if (e->index == MSR_IA32_UCODE_WRITE || /* SDM Table 35-2 */
+ e->index == MSR_IA32_UCODE_REV)
+ return -EINVAL;
+ if (e->reserved != 0)
return -EINVAL;
return 0;
}
-static inline int nested_vmx_load_msr_check(struct vmx_msr_entry *e)
+static int nested_vmx_load_msr_check(struct kvm_vcpu *vcpu,
+ struct vmx_msr_entry *e)
{
if (e->index == MSR_FS_BASE ||
e->index == MSR_GS_BASE ||
- nested_vmx_msr_check_common(e))
+ e->index == MSR_IA32_SMM_MONITOR_CTL || /* SMM is not supported */
+ nested_vmx_msr_check_common(vcpu, e))
+ return -EINVAL;
+ return 0;
+}
+
+static int nested_vmx_store_msr_check(struct kvm_vcpu *vcpu,
+ struct vmx_msr_entry *e)
+{
+ if (e->index == MSR_IA32_SMBASE || /* SMM is not supported */
+ nested_vmx_msr_check_common(vcpu, e))
return -EINVAL;
return 0;
}
@@ -8321,13 +8383,27 @@ static u32 nested_vmx_load_msr(struct kvm_vcpu *vcpu, u64 gpa, u32 count)
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))
+ if (kvm_read_guest(vcpu->kvm, gpa + i * sizeof(e),
+ &e, sizeof(e))) {
+ pr_warn_ratelimited(
+ "%s cannot read MSR entry (%u, 0x%08llx)\n",
+ __func__, i, gpa + i * sizeof(e));
+ goto fail;
+ }
+ if (nested_vmx_load_msr_check(vcpu, &e)) {
+ pr_warn_ratelimited(
+ "%s check failed (%u, 0x%x, 0x%x)\n",
+ __func__, i, e.index, e.reserved);
goto fail;
+ }
msr.index = e.index;
msr.data = e.value;
- if (kvm_set_msr(vcpu, &msr))
+ if (kvm_set_msr(vcpu, &msr)) {
+ pr_warn_ratelimited(
+ "%s cannot write MSR (%u, 0x%x, 0x%llx)\n",
+ __func__, i, e.index, e.value);
goto fail;
+ }
}
return 0;
fail:
@@ -8340,16 +8416,35 @@ static int nested_vmx_store_msr(struct kvm_vcpu *vcpu, u64 gpa, u32 count)
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))
+ if (kvm_read_guest(vcpu->kvm,
+ gpa + i * sizeof(e),
+ &e, 2 * sizeof(u32))) {
+ pr_warn_ratelimited(
+ "%s cannot read MSR entry (%u, 0x%08llx)\n",
+ __func__, i, gpa + i * sizeof(e));
+ return -EINVAL;
+ }
+ if (nested_vmx_store_msr_check(vcpu, &e)) {
+ pr_warn_ratelimited(
+ "%s check failed (%u, 0x%x, 0x%x)\n",
+ __func__, i, e.index, e.reserved);
return -EINVAL;
- if (kvm_get_msr(vcpu, e.index, &e.value))
+ }
+ if (kvm_get_msr(vcpu, e.index, &e.value)) {
+ pr_warn_ratelimited(
+ "%s cannot read MSR (%u, 0x%x)\n",
+ __func__, i, e.index);
return -EINVAL;
- kvm_write_guest(vcpu->kvm,
- gpa + i * sizeof(e) +
+ }
+ if (kvm_write_guest(vcpu->kvm,
+ gpa + i * sizeof(e) +
offsetof(struct vmx_msr_entry, value),
- &e.value, sizeof(e.value));
+ &e.value, sizeof(e.value))) {
+ pr_warn_ratelimited(
+ "%s cannot write MSR (%u, 0x%x, 0x%llx)\n",
+ __func__, i, e.index, e.value);
+ return -EINVAL;
+ }
}
return 0;
}
--
2.0.4
--
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