[PATCH v2 19/66] KVM: VMX: Add helpers to query Intel PT mode

Sean Christopherson
2020-03-03T00:00:10Z

Add helpers to query which of the (two) supported PT modes is active.
The primary motivation is to help document that there is a third PT mode
(host-only) that's currently not supported by KVM. As is, it's not
obvious that PT_MODE_SYSTEM != !PT_MODE_HOST_GUEST and vice versa, e.g.
that "pt_mode == PT_MODE_SYSTEM" and "pt_mode != PT_MODE_HOST_GUEST" are
two distinct checks.

No functional change intended.

Reviewed-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
---
arch/x86/kvm/vmx/capabilities.h | 18 ++++++++++++++++++
arch/x86/kvm/vmx/nested.c | 2 +-
arch/x86/kvm/vmx/vmx.c | 26 +++++++++++++-------------
arch/x86/kvm/vmx/vmx.h | 4 ++--
4 files changed, 34 insertions(+), 16 deletions(-)

diff --git a/arch/x86/kvm/vmx/capabilities.h b/arch/x86/kvm/vmx/capabilities.h
index f486e2606247..80eec8cffbe2 100644
--- a/arch/x86/kvm/vmx/capabilities.h
+++ b/arch/x86/kvm/vmx/capabilities.h
@@ -354,4 +354,22 @@ static inline bool cpu_has_vmx_intel_pt(void)
(vmcs_config.vmentry_ctrl & VM_ENTRY_LOAD_IA32_RTIT_CTL);
}

+/*
+ * Processor Trace can operate in one of three modes:
+ * a. system-wide: trace both host/guest and output to host buffer
+ * b. host-only: only trace host and output to host buffer
+ * c. host-guest: trace host and guest simultaneously and output to their
+ * respective buffer
+ *
+ * KVM currently only supports (a) and (c).
+ */
+static inline bool vmx_pt_mode_is_system(void)
+{
+ return pt_mode == PT_MODE_SYSTEM;
+}
+static inline bool vmx_pt_mode_is_host_guest(void)
+{
+ return pt_mode == PT_MODE_HOST_GUEST;
+}
+
#endif /* __KVM_X86_VMX_CAPS_H */
diff --git a/arch/x86/kvm/vmx/nested.c b/arch/x86/kvm/vmx/nested.c
index 0946122a8d3b..ae84b3c66e0d 100644
--- a/arch/x86/kvm/vmx/nested.c
+++ b/arch/x86/kvm/vmx/nested.c
@@ -4602,7 +4602,7 @@ static int enter_vmx_operation(struct kvm_vcpu *vcpu)
vmx->nested.vmcs02_initialized = false;
vmx->nested.vmxon = true;

- if (pt_mode == PT_MODE_HOST_GUEST) {
+ if (vmx_pt_mode_is_host_guest()) {
vmx->pt_desc.guest.ctl = 0;
pt_update_intercept_for_msr(vmx);
}
diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c
index a04017bdae05..2dcf27e3a7a6 100644
--- a/arch/x86/kvm/vmx/vmx.c
+++ b/arch/x86/kvm/vmx/vmx.c
@@ -1059,7 +1059,7 @@ static unsigned long segment_base(u16 selector)

static inline bool pt_can_write_msr(struct vcpu_vmx *vmx)
{
- return (pt_mode == PT_MODE_HOST_GUEST) &&
+ return vmx_pt_mode_is_host_guest() &&
!(vmx->pt_desc.guest.ctl & RTIT_CTL_TRACEEN);
}

@@ -1093,7 +1093,7 @@ static inline void pt_save_msr(struct pt_ctx *ctx, u32 addr_range)

static void pt_guest_enter(struct vcpu_vmx *vmx)
{
- if (pt_mode == PT_MODE_SYSTEM)
+ if (vmx_pt_mode_is_system())
return;

/*
@@ -1110,7 +1110,7 @@ static void pt_guest_enter(struct vcpu_vmx *vmx)

static void pt_guest_exit(struct vcpu_vmx *vmx)
{
- if (pt_mode == PT_MODE_SYSTEM)
+ if (vmx_pt_mode_is_system())
return;

if (vmx->pt_desc.guest.ctl & RTIT_CTL_TRACEEN) {
@@ -1904,24 +1904,24 @@ static int vmx_get_msr(struct kvm_vcpu *vcpu, struct msr_data *msr_info)
&msr_info->data);
break;
case MSR_IA32_RTIT_CTL:
- if (pt_mode != PT_MODE_HOST_GUEST)
+ if (!vmx_pt_mode_is_host_guest())
return 1;
msr_info->data = vmx->pt_desc.guest.ctl;
break;
case MSR_IA32_RTIT_STATUS:
- if (pt_mode != PT_MODE_HOST_GUEST)
+ if (!vmx_pt_mode_is_host_guest())
return 1;
msr_info->data = vmx->pt_desc.guest.status;
break;
case MSR_IA32_RTIT_CR3_MATCH:
- if ((pt_mode != PT_MODE_HOST_GUEST) ||
+ if (!vmx_pt_mode_is_host_guest() ||
!intel_pt_validate_cap(vmx->pt_desc.caps,
PT_CAP_cr3_filtering))
return 1;
msr_info->data = vmx->pt_desc.guest.cr3_match;
break;
case MSR_IA32_RTIT_OUTPUT_BASE:
- if ((pt_mode != PT_MODE_HOST_GUEST) ||
+ if (!vmx_pt_mode_is_host_guest() ||
(!intel_pt_validate_cap(vmx->pt_desc.caps,
PT_CAP_topa_output) &&
!intel_pt_validate_cap(vmx->pt_desc.caps,
@@ -1930,7 +1930,7 @@ static int vmx_get_msr(struct kvm_vcpu *vcpu, struct msr_data *msr_info)
msr_info->data = vmx->pt_desc.guest.output_base;
break;
case MSR_IA32_RTIT_OUTPUT_MASK:
- if ((pt_mode != PT_MODE_HOST_GUEST) ||
+ if (!vmx_pt_mode_is_host_guest() ||
(!intel_pt_validate_cap(vmx->pt_desc.caps,
PT_CAP_topa_output) &&
!intel_pt_validate_cap(vmx->pt_desc.caps,
@@ -1940,7 +1940,7 @@ static int vmx_get_msr(struct kvm_vcpu *vcpu, struct msr_data *msr_info)
break;
case MSR_IA32_RTIT_ADDR0_A ... MSR_IA32_RTIT_ADDR3_B:
index = msr_info->index - MSR_IA32_RTIT_ADDR0_A;
- if ((pt_mode != PT_MODE_HOST_GUEST) ||
+ if (!vmx_pt_mode_is_host_guest() ||
(index >= 2 * intel_pt_validate_cap(vmx->pt_desc.caps,
PT_CAP_num_address_ranges)))
return 1;
@@ -2146,7 +2146,7 @@ static int vmx_set_msr(struct kvm_vcpu *vcpu, struct msr_data *msr_info)
return 1;
return vmx_set_vmx_msr(vcpu, msr_index, data);
case MSR_IA32_RTIT_CTL:
- if ((pt_mode != PT_MODE_HOST_GUEST) ||
+ if (!vmx_pt_mode_is_host_guest() ||
vmx_rtit_ctl_check(vcpu, data) ||
vmx->nested.vmxon)
return 1;
@@ -4024,7 +4024,7 @@ static void vmx_compute_secondary_exec_control(struct vcpu_vmx *vmx)

u32 exec_control = vmcs_config.cpu_based_2nd_exec_ctrl;

- if (pt_mode == PT_MODE_SYSTEM)
+ if (vmx_pt_mode_is_system())
exec_control &= ~(SECONDARY_EXEC_PT_USE_GPA | SECONDARY_EXEC_PT_CONCEAL_VMX);
if (!cpu_need_virtualize_apic_accesses(vcpu))
exec_control &= ~SECONDARY_EXEC_VIRTUALIZE_APIC_ACCESSES;
@@ -4265,7 +4265,7 @@ static void init_vmcs(struct vcpu_vmx *vmx)
if (cpu_has_vmx_encls_vmexit())
vmcs_write64(ENCLS_EXITING_BITMAP, -1ull);

- if (pt_mode == PT_MODE_HOST_GUEST) {
+ if (vmx_pt_mode_is_host_guest()) {
memset(&vmx->pt_desc, 0, sizeof(vmx->pt_desc));
/* Bit[6~0] are forced to 1, writes are ignored. */
vmx->pt_desc.guest.output_mask = 0x7F;
@@ -6314,7 +6314,7 @@ static bool vmx_has_emulated_msr(int index)

static bool vmx_pt_supported(void)
{
- return pt_mode == PT_MODE_HOST_GUEST;
+ return vmx_pt_mode_is_host_guest();
}

static void vmx_recover_nmi_blocking(struct vcpu_vmx *vmx)
diff --git a/arch/x86/kvm/vmx/vmx.h b/arch/x86/kvm/vmx/vmx.h
index e64da06c7009..9a51a3a77233 100644
--- a/arch/x86/kvm/vmx/vmx.h
+++ b/arch/x86/kvm/vmx/vmx.h
@@ -452,7 +452,7 @@ static inline void vmx_segment_cache_clear(struct vcpu_vmx *vmx)
static inline u32 vmx_vmentry_ctrl(void)
{
u32 vmentry_ctrl = vmcs_config.vmentry_ctrl;
- if (pt_mode == PT_MODE_SYSTEM)
+ if (vmx_pt_mode_is_system())
vmentry_ctrl &= ~(VM_ENTRY_PT_CONCEAL_PIP |
VM_ENTRY_LOAD_IA32_RTIT_CTL);
/* Loading of EFER and PERF_GLOBAL_CTRL are toggled dynamically */
@@ -463,7 +463,7 @@ static inline u32 vmx_vmentry_ctrl(void)
static inline u32 vmx_vmexit_ctrl(void)
{
u32 vmexit_ctrl = vmcs_config.vmexit_ctrl;
- if (pt_mode == PT_MODE_SYSTEM)
+ if (vmx_pt_mode_is_system())
vmexit_ctrl &= ~(VM_EXIT_PT_CONCEAL_PIP |
VM_EXIT_CLEAR_IA32_RTIT_CTL);
/* Loading of EFER and PERF_GLOBAL_CTRL are toggled dynamically */
--
2.24.1