Before enabling, execution of "rdtscp" in guest would result in #UD.
Signed-off-by: Sheng Yang <sheng@xxxxxxxxxxxxxxx>
---
Reflect guest CPUID on vmcs fields as well, but it involved some more code
which would only executed once... Do we need a callback there for post-"cpuid
setting"?
arch/x86/include/asm/kvm_host.h | 3 ++
arch/x86/include/asm/vmx.h | 1 +
arch/x86/kvm/svm.c | 6 ++++
arch/x86/kvm/vmx.c | 49 ++++++++++++++++++++++++++++++++++++--
arch/x86/kvm/x86.c | 15 ++++++++++-
5 files changed, 69 insertions(+), 5 deletions(-)
diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
index 4f865e8..c920285 100644
--- a/arch/x86/include/asm/kvm_host.h
+++ b/arch/x86/include/asm/kvm_host.h
@@ -374,6 +374,8 @@ struct kvm_vcpu_arch {
/* used for guest single stepping over the given code position */
u16 singlestep_cs;
unsigned long singlestep_rip;
+
+ bool cpuid_rdtscp_enabled;
};
struct kvm_mem_alias {
@@ -532,6 +534,7 @@ struct kvm_x86_ops {
int (*get_tdp_level)(void);
u64 (*get_mt_mask)(struct kvm_vcpu *vcpu, gfn_t gfn, bool is_mmio);
bool (*gb_page_enable)(void);
+ bool (*rdtscp_supported)(void);
const struct trace_print_flags *exit_reasons_str;
};
diff --git a/arch/x86/include/asm/vmx.h b/arch/x86/include/asm/vmx.h
index 2b49454..8c39320 100644
--- a/arch/x86/include/asm/vmx.h
+++ b/arch/x86/include/asm/vmx.h
@@ -53,6 +53,7 @@
*/
#define SECONDARY_EXEC_VIRTUALIZE_APIC_ACCESSES 0x00000001
#define SECONDARY_EXEC_ENABLE_EPT 0x00000002
+#define SECONDARY_EXEC_RDTSCP 0x00000008
#define SECONDARY_EXEC_ENABLE_VPID 0x00000020
#define SECONDARY_EXEC_WBINVD_EXITING 0x00000040
#define SECONDARY_EXEC_UNRESTRICTED_GUEST 0x00000080
diff --git a/arch/x86/kvm/svm.c b/arch/x86/kvm/svm.c
index 3de0b37..052d91a 100644
--- a/arch/x86/kvm/svm.c
+++ b/arch/x86/kvm/svm.c
@@ -2912,6 +2912,11 @@ static bool svm_gb_page_enable(void)
return true;
}
+static bool svm_rdtscp_supported(void)
+{
+ return false;
+}
+
static struct kvm_x86_ops svm_x86_ops = {
.cpu_has_kvm_support = has_svm,
.disabled_by_bios = is_disabled,
@@ -2978,6 +2983,7 @@ static struct kvm_x86_ops svm_x86_ops = {
.exit_reasons_str = svm_exit_reasons_str,
.gb_page_enable = svm_gb_page_enable,
+ .rdtscp_supported = svm_rdtscp_supported,
};
static int __init svm_init(void)
diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
index 5c464ed..f60e645 100644
--- a/arch/x86/kvm/vmx.c
+++ b/arch/x86/kvm/vmx.c
@@ -136,6 +136,8 @@ struct vcpu_vmx {
ktime_t entry_time;
s64 vnmi_blocked_time;
u32 exit_reason;
+
+ bool control_rdtscp_enabled;
};
static inline struct vcpu_vmx *to_vmx(struct kvm_vcpu *vcpu)
@@ -210,7 +212,7 @@ static const u32 vmx_msr_index[] = {
#ifdef CONFIG_X86_64
MSR_SYSCALL_MASK, MSR_LSTAR, MSR_CSTAR,
#endif
- MSR_EFER, MSR_K6_STAR,
+ MSR_EFER, MSR_TSC_AUX, MSR_K6_STAR,
};
#define NR_VMX_MSR ARRAY_SIZE(vmx_msr_index)
@@ -347,6 +349,12 @@ static inline int cpu_has_vmx_vpid(void)
SECONDARY_EXEC_ENABLE_VPID;
}
+static inline int cpu_has_vmx_rdtscp(void)
+{
+ return vmcs_config.cpu_based_2nd_exec_ctrl &
+ SECONDARY_EXEC_RDTSCP;
+}
+
static inline int cpu_has_virtual_nmis(void)
{
return vmcs_config.pin_based_exec_ctrl & PIN_BASED_VIRTUAL_NMIS;
@@ -878,6 +886,11 @@ static void vmx_queue_exception(struct kvm_vcpu *vcpu, unsigned nr,
vmcs_write32(VM_ENTRY_INTR_INFO_FIELD, intr_info);
}
+static bool vmx_rdtscp_supported(void)
+{
+ return cpu_has_vmx_rdtscp();
+}
+
/*
* Swap MSR entry in host/guest MSR entry array.
*/
@@ -913,6 +926,9 @@ static void setup_msrs(struct vcpu_vmx *vmx)
index = __find_msr_index(vmx, MSR_CSTAR);
if (index >= 0)
move_msr_up(vmx, index, save_nmsrs++);
+ index = __find_msr_index(vmx, MSR_TSC_AUX);
+ if (index >= 0)
+ move_msr_up(vmx, index, save_nmsrs++);
/*
* MSR_K6_STAR is only needed on long mode guests, and only
* if efer.sce is enabled.
@@ -1002,6 +1018,10 @@ static int vmx_get_msr(struct kvm_vcpu *vcpu, u32 msr_index, u64 *pdata)
case MSR_IA32_SYSENTER_ESP:
data = vmcs_readl(GUEST_SYSENTER_ESP);
break;
+ case MSR_TSC_AUX:
+ if (!vcpu->arch.cpuid_rdtscp_enabled || !vmx_rdtscp_supported())
+ return 1;
+ /* Otherwise falls through */
default:
vmx_load_host_state(to_vmx(vcpu));
msr = find_msr_entry(to_vmx(vcpu), msr_index);
@@ -1065,7 +1085,15 @@ static int vmx_set_msr(struct kvm_vcpu *vcpu, u32 msr_index, u64 data)
vcpu->arch.pat = data;
break;
}
- /* Otherwise falls through to kvm_set_msr_common */
+ ret = kvm_set_msr_common(vcpu, msr_index, data);
+ break;
+ case MSR_TSC_AUX:
+ if (!vcpu->arch.cpuid_rdtscp_enabled || !vmx_rdtscp_supported())
+ return 1;
+ /* Check reserved bit */
+ if ((data & 0xffff0000) != 0)
+ return 1;
+ /* Otherwise falls through */
default:
msr = find_msr_entry(vmx, msr_index);
if (msr) {
@@ -1243,7 +1271,8 @@ static __init int setup_vmcs_config(struct vmcs_config *vmcs_conf)
SECONDARY_EXEC_ENABLE_VPID |
SECONDARY_EXEC_ENABLE_EPT |
SECONDARY_EXEC_UNRESTRICTED_GUEST |
- SECONDARY_EXEC_PAUSE_LOOP_EXITING;
+ SECONDARY_EXEC_PAUSE_LOOP_EXITING |
+ SECONDARY_EXEC_RDTSCP;
if (adjust_vmx_controls(min2, opt2,
MSR_IA32_VMX_PROCBASED_CTLS2,
&_cpu_based_2nd_exec_control) < 0)
@@ -2316,6 +2345,10 @@ static int vmx_vcpu_setup(struct vcpu_vmx *vmx)
exec_control &= ~SECONDARY_EXEC_UNRESTRICTED_GUEST;
if (!ple_gap)
exec_control &= ~SECONDARY_EXEC_PAUSE_LOOP_EXITING;
+ /* Delay the update of field, because we don't know guest CPUID
+ * at this time */
+ vmx->control_rdtscp_enabled = !!(exec_control &
+ SECONDARY_EXEC_RDTSCP);
vmcs_write32(SECONDARY_VM_EXEC_CONTROL, exec_control);
}
@@ -3655,6 +3688,7 @@ static void fixup_rmode_irq(struct vcpu_vmx *vmx)
static void vmx_vcpu_run(struct kvm_vcpu *vcpu)
{
struct vcpu_vmx *vmx = to_vmx(vcpu);
+ u32 exec_control;
/* Record the guest's net vcpu time for enforced NMI injections. */
if (unlikely(!cpu_has_virtual_nmis() && vmx->soft_vnmi_blocked))
@@ -3670,6 +3704,14 @@ static void vmx_vcpu_run(struct kvm_vcpu *vcpu)
if (test_bit(VCPU_REGS_RIP, (unsigned long *)&vcpu->arch.regs_dirty))
vmcs_writel(GUEST_RIP, vcpu->arch.regs[VCPU_REGS_RIP]);
+ /* Check if rdtscp reported to guest */
+ if (!vcpu->arch.cpuid_rdtscp_enabled && vmx->control_rdtscp_enabled) {
+ exec_control = vmcs_read32(SECONDARY_VM_EXEC_CONTROL);
+ exec_control &= ~SECONDARY_EXEC_RDTSCP;
+ vmcs_write32(SECONDARY_VM_EXEC_CONTROL, exec_control);
+ vmx->control_rdtscp_enabled = 0;
+ }
+
/* When single-stepping over STI and MOV SS, we must clear the
* corresponding interruptibility bits in the guest state. Otherwise
* vmentry fails as it then expects bit 14 (BS) in pending debug
@@ -4025,6 +4067,7 @@ static struct kvm_x86_ops vmx_x86_ops = {
.exit_reasons_str = vmx_exit_reasons_str,
.gb_page_enable = vmx_gb_page_enable,
+ .rdtscp_supported = vmx_rdtscp_supported,
};
static int __init vmx_init(void)
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index e3eae50..cb6c879 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -1544,6 +1544,16 @@ static void cpuid_fix_nx_cap(struct kvm_vcpu *vcpu)
}
}
+static void update_cpuid_support_rdtscp(struct kvm_vcpu *vcpu)
+{
+ struct kvm_cpuid_entry2 *best;
+
+ vcpu->arch.cpuid_rdtscp_enabled = false;
+ best = kvm_find_cpuid_entry(vcpu, 0x80000001, 0);
+ if (best && (best->edx & bit(X86_FEATURE_RDTSCP)))
+ vcpu->arch.cpuid_rdtscp_enabled = true;
+}
+
/* when an old userspace process fills a new kernel module */
static int kvm_vcpu_ioctl_set_cpuid(struct kvm_vcpu *vcpu,
struct kvm_cpuid *cpuid,
@@ -1579,7 +1589,6 @@ static int kvm_vcpu_ioctl_set_cpuid(struct kvm_vcpu *vcpu,
cpuid_fix_nx_cap(vcpu);
r = 0;
kvm_apic_set_version(vcpu);
-
out_free:
vfree(cpuid_entries);
out:
@@ -1601,6 +1610,7 @@ static int kvm_vcpu_ioctl_set_cpuid2(struct kvm_vcpu *vcpu,
goto out;
vcpu->arch.cpuid_nent = cpuid->nent;
kvm_apic_set_version(vcpu);
+ update_cpuid_support_rdtscp(vcpu);
return 0;
out:
@@ -1649,6 +1659,7 @@ static void do_cpuid_ent(struct kvm_cpuid_entry2 *entry, u32 function,
#else
unsigned f_lm = 0;
#endif
+ unsigned f_rdtscp = kvm_x86_ops->rdtscp_supported() ? F(RDTSCP) : 0;
/* cpuid 1.edx */
const u32 kvm_supported_word0_x86_features =
@@ -1668,7 +1679,7 @@ static void do_cpuid_ent(struct kvm_cpuid_entry2 *entry, u32 function,
F(MTRR) | F(PGE) | F(MCA) | F(CMOV) |
F(PAT) | F(PSE36) | 0 /* Reserved */ |
f_nx | 0 /* Reserved */ | F(MMXEXT) | F(MMX) |
- F(FXSR) | F(FXSR_OPT) | f_gbpages | 0 /* RDTSCP */ |
+ F(FXSR) | F(FXSR_OPT) | f_gbpages | f_rdtscp |
0 /* Reserved */ | f_lm | F(3DNOWEXT) | F(3DNOW);
/* cpuid 1.ecx */
const u32 kvm_supported_word4_x86_features =
--
1.5.4.5
--
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