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Subject[PATCH v13 10/12] KVM: x86: Implement Intel PT MSRs read/write emulation
Date
From: Chao Peng <chao.p.peng@linux.intel.com>

This patch implement Intel Processor Trace MSRs read/write
emulation.
Intel PT MSRs read/write need to be emulated when Intel PT
MSRs is intercepted in guest and during live migration.

Signed-off-by: Chao Peng <chao.p.peng@linux.intel.com>
Signed-off-by: Luwei Kang <luwei.kang@intel.com>
---
arch/x86/include/asm/intel_pt.h | 8 ++
arch/x86/kvm/vmx.c | 176 ++++++++++++++++++++++++++++++++++++++++
arch/x86/kvm/x86.c | 33 +++++++-
3 files changed, 216 insertions(+), 1 deletion(-)

diff --git a/arch/x86/include/asm/intel_pt.h b/arch/x86/include/asm/intel_pt.h
index eabbdbc..a1c2080 100644
--- a/arch/x86/include/asm/intel_pt.h
+++ b/arch/x86/include/asm/intel_pt.h
@@ -10,6 +10,14 @@

#define RTIT_ADDR_RANGE 4

+#define MSR_IA32_RTIT_STATUS_MASK (~(RTIT_STATUS_FILTEREN | \
+ RTIT_STATUS_CONTEXTEN | RTIT_STATUS_TRIGGEREN | \
+ RTIT_STATUS_ERROR | RTIT_STATUS_STOPPED | \
+ RTIT_STATUS_BYTECNT))
+
+#define MSR_IA32_RTIT_OUTPUT_BASE_MASK \
+ (~((1UL << cpuid_query_maxphyaddr(vcpu)) - 1) | 0x7f)
+
enum pt_capabilities {
PT_CAP_max_subleaf = 0,
PT_CAP_cr3_filtering,
diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
index 2697618..a568d49 100644
--- a/arch/x86/kvm/vmx.c
+++ b/arch/x86/kvm/vmx.c
@@ -3350,6 +3350,79 @@ static void vmx_set_interrupt_shadow(struct kvm_vcpu *vcpu, int mask)
vmcs_write32(GUEST_INTERRUPTIBILITY_INFO, interruptibility);
}

+static int vmx_rtit_ctl_check(struct kvm_vcpu *vcpu, u64 data)
+{
+ struct vcpu_vmx *vmx = to_vmx(vcpu);
+ unsigned long value;
+
+ /*
+ * Any MSR write that attempts to change bits marked reserved will
+ * case a #GP fault.
+ */
+ if (data & vmx->pt_desc.ctl_bitmask)
+ return 1;
+
+ /*
+ * Any attempt to modify IA32_RTIT_CTL while TraceEn is set will
+ * result in a #GP unless the same write also clears TraceEn.
+ */
+ if ((vmx->pt_desc.guest.ctl & RTIT_CTL_TRACEEN) &&
+ ((vmx->pt_desc.guest.ctl ^ data) & ~RTIT_CTL_TRACEEN))
+ return 1;
+
+ /*
+ * WRMSR to IA32_RTIT_CTL that sets TraceEn but clears this bit
+ * and FabricEn would cause #GP, if
+ * CPUID.(EAX=14H, ECX=0):ECX.SNGLRGNOUT[bit 2] = 0
+ */
+ if ((data & RTIT_CTL_TRACEEN) && !(data & RTIT_CTL_TOPA) &&
+ !(data & RTIT_CTL_FABRIC_EN) &&
+ !intel_pt_validate_cap(vmx->pt_desc.caps,
+ PT_CAP_single_range_output))
+ return 1;
+
+ /*
+ * MTCFreq, CycThresh and PSBFreq encodings check, any MSR write that
+ * utilize encodings marked reserved will casue a #GP fault.
+ */
+ value = intel_pt_validate_cap(vmx->pt_desc.caps, PT_CAP_mtc_periods);
+ if (intel_pt_validate_cap(vmx->pt_desc.caps, PT_CAP_mtc) &&
+ !test_bit((data & RTIT_CTL_MTC_RANGE) >>
+ RTIT_CTL_MTC_RANGE_OFFSET, &value))
+ return 1;
+ value = intel_pt_validate_cap(vmx->pt_desc.caps,
+ PT_CAP_cycle_thresholds);
+ if (intel_pt_validate_cap(vmx->pt_desc.caps, PT_CAP_psb_cyc) &&
+ !test_bit((data & RTIT_CTL_CYC_THRESH) >>
+ RTIT_CTL_CYC_THRESH_OFFSET, &value))
+ return 1;
+ value = intel_pt_validate_cap(vmx->pt_desc.caps, PT_CAP_psb_periods);
+ if (intel_pt_validate_cap(vmx->pt_desc.caps, PT_CAP_psb_cyc) &&
+ !test_bit((data & RTIT_CTL_PSB_FREQ) >>
+ RTIT_CTL_PSB_FREQ_OFFSET, &value))
+ return 1;
+
+ /*
+ * If ADDRx_CFG is reserved or the encodings is >2 will
+ * cause a #GP fault.
+ */
+ value = (data & RTIT_CTL_ADDR0) >> RTIT_CTL_ADDR0_OFFSET;
+ if ((value && (vmx->pt_desc.addr_range < 1)) || (value > 2))
+ return 1;
+ value = (data & RTIT_CTL_ADDR1) >> RTIT_CTL_ADDR1_OFFSET;
+ if ((value && (vmx->pt_desc.addr_range < 2)) || (value > 2))
+ return 1;
+ value = (data & RTIT_CTL_ADDR2) >> RTIT_CTL_ADDR2_OFFSET;
+ if ((value && (vmx->pt_desc.addr_range < 3)) || (value > 2))
+ return 1;
+ value = (data & RTIT_CTL_ADDR3) >> RTIT_CTL_ADDR3_OFFSET;
+ if ((value && (vmx->pt_desc.addr_range < 4)) || (value > 2))
+ return 1;
+
+ return 0;
+}
+
+
static void skip_emulated_instruction(struct kvm_vcpu *vcpu)
{
unsigned long rip;
@@ -4186,6 +4259,7 @@ static int vmx_get_msr(struct kvm_vcpu *vcpu, struct msr_data *msr_info)
{
struct vcpu_vmx *vmx = to_vmx(vcpu);
struct shared_msr_entry *msr;
+ u32 index;

switch (msr_info->index) {
#ifdef CONFIG_X86_64
@@ -4250,6 +4324,52 @@ static int vmx_get_msr(struct kvm_vcpu *vcpu, struct msr_data *msr_info)
return 1;
msr_info->data = vcpu->arch.ia32_xss;
break;
+ case MSR_IA32_RTIT_CTL:
+ if (pt_mode != PT_MODE_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)
+ return 1;
+ msr_info->data = vmx->pt_desc.guest.status;
+ break;
+ case MSR_IA32_RTIT_CR3_MATCH:
+ if ((pt_mode != PT_MODE_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) ||
+ (!intel_pt_validate_cap(vmx->pt_desc.caps,
+ PT_CAP_topa_output) &&
+ !intel_pt_validate_cap(vmx->pt_desc.caps,
+ PT_CAP_single_range_output)))
+ return 1;
+ msr_info->data = vmx->pt_desc.guest.output_base;
+ break;
+ case MSR_IA32_RTIT_OUTPUT_MASK:
+ if ((pt_mode != PT_MODE_HOST_GUEST) ||
+ (!intel_pt_validate_cap(vmx->pt_desc.caps,
+ PT_CAP_topa_output) &&
+ !intel_pt_validate_cap(vmx->pt_desc.caps,
+ PT_CAP_single_range_output)))
+ return 1;
+ msr_info->data = vmx->pt_desc.guest.output_mask;
+ 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) ||
+ (index >= 2 * intel_pt_validate_cap(vmx->pt_desc.caps,
+ PT_CAP_num_address_ranges)))
+ return 1;
+ if (index % 2)
+ msr_info->data = vmx->pt_desc.guest.addr_b[index / 2];
+ else
+ msr_info->data = vmx->pt_desc.guest.addr_a[index / 2];
+ break;
case MSR_TSC_AUX:
if (!msr_info->host_initiated &&
!guest_cpuid_has(vcpu, X86_FEATURE_RDTSCP))
@@ -4281,6 +4401,7 @@ static int vmx_set_msr(struct kvm_vcpu *vcpu, struct msr_data *msr_info)
int ret = 0;
u32 msr_index = msr_info->index;
u64 data = msr_info->data;
+ u32 index;

switch (msr_index) {
case MSR_EFER:
@@ -4432,6 +4553,61 @@ static int vmx_set_msr(struct kvm_vcpu *vcpu, struct msr_data *msr_info)
else
clear_atomic_switch_msr(vmx, MSR_IA32_XSS);
break;
+ case MSR_IA32_RTIT_CTL:
+ if ((pt_mode != PT_MODE_HOST_GUEST) ||
+ vmx_rtit_ctl_check(vcpu, data))
+ return 1;
+ vmcs_write64(GUEST_IA32_RTIT_CTL, data);
+ vmx->pt_desc.guest.ctl = data;
+ break;
+ case MSR_IA32_RTIT_STATUS:
+ if ((pt_mode != PT_MODE_HOST_GUEST) ||
+ (vmx->pt_desc.guest.ctl & RTIT_CTL_TRACEEN) ||
+ (data & MSR_IA32_RTIT_STATUS_MASK))
+ return 1;
+ vmx->pt_desc.guest.status = data;
+ break;
+ case MSR_IA32_RTIT_CR3_MATCH:
+ if ((pt_mode != PT_MODE_HOST_GUEST) ||
+ (vmx->pt_desc.guest.ctl & RTIT_CTL_TRACEEN) ||
+ !intel_pt_validate_cap(vmx->pt_desc.caps,
+ PT_CAP_cr3_filtering))
+ return 1;
+ vmx->pt_desc.guest.cr3_match = data;
+ break;
+ case MSR_IA32_RTIT_OUTPUT_BASE:
+ if ((pt_mode != PT_MODE_HOST_GUEST) ||
+ (vmx->pt_desc.guest.ctl & RTIT_CTL_TRACEEN) ||
+ (!intel_pt_validate_cap(vmx->pt_desc.caps,
+ PT_CAP_topa_output) &&
+ !intel_pt_validate_cap(vmx->pt_desc.caps,
+ PT_CAP_single_range_output)) ||
+ (data & MSR_IA32_RTIT_OUTPUT_BASE_MASK))
+ return 1;
+ vmx->pt_desc.guest.output_base = data;
+ break;
+ case MSR_IA32_RTIT_OUTPUT_MASK:
+ if ((pt_mode != PT_MODE_HOST_GUEST) ||
+ (vmx->pt_desc.guest.ctl & RTIT_CTL_TRACEEN) ||
+ (!intel_pt_validate_cap(vmx->pt_desc.caps,
+ PT_CAP_topa_output) &&
+ !intel_pt_validate_cap(vmx->pt_desc.caps,
+ PT_CAP_single_range_output)))
+ return 1;
+ vmx->pt_desc.guest.output_mask = data;
+ 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) ||
+ (vmx->pt_desc.guest.ctl & RTIT_CTL_TRACEEN) ||
+ (index >= 2 * intel_pt_validate_cap(vmx->pt_desc.caps,
+ PT_CAP_num_address_ranges)))
+ return 1;
+ if (index % 2)
+ vmx->pt_desc.guest.addr_b[index / 2] = data;
+ else
+ vmx->pt_desc.guest.addr_a[index / 2] = data;
+ break;
case MSR_TSC_AUX:
if (!msr_info->host_initiated &&
!guest_cpuid_has(vcpu, X86_FEATURE_RDTSCP))
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 66d66d7..603c92a 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -69,6 +69,7 @@
#include <asm/irq_remapping.h>
#include <asm/mshyperv.h>
#include <asm/hypervisor.h>
+#include <asm/intel_pt.h>

#define CREATE_TRACE_POINTS
#include "trace.h"
@@ -1121,7 +1122,13 @@ bool kvm_rdpmc(struct kvm_vcpu *vcpu)
#endif
MSR_IA32_TSC, MSR_IA32_CR_PAT, MSR_VM_HSAVE_PA,
MSR_IA32_FEATURE_CONTROL, MSR_IA32_BNDCFGS, MSR_TSC_AUX,
- MSR_IA32_SPEC_CTRL, MSR_IA32_ARCH_CAPABILITIES
+ MSR_IA32_SPEC_CTRL, MSR_IA32_ARCH_CAPABILITIES,
+ MSR_IA32_RTIT_CTL, MSR_IA32_RTIT_STATUS, MSR_IA32_RTIT_CR3_MATCH,
+ MSR_IA32_RTIT_OUTPUT_BASE, MSR_IA32_RTIT_OUTPUT_MASK,
+ MSR_IA32_RTIT_ADDR0_A, MSR_IA32_RTIT_ADDR0_B,
+ MSR_IA32_RTIT_ADDR1_A, MSR_IA32_RTIT_ADDR1_B,
+ MSR_IA32_RTIT_ADDR2_A, MSR_IA32_RTIT_ADDR2_B,
+ MSR_IA32_RTIT_ADDR3_A, MSR_IA32_RTIT_ADDR3_B,
};

static unsigned num_msrs_to_save;
@@ -4842,6 +4849,30 @@ static void kvm_init_msr_list(void)
if (!kvm_x86_ops->rdtscp_supported())
continue;
break;
+ case MSR_IA32_RTIT_CTL:
+ case MSR_IA32_RTIT_STATUS:
+ if (!kvm_x86_ops->pt_supported())
+ continue;
+ break;
+ case MSR_IA32_RTIT_CR3_MATCH:
+ if (!kvm_x86_ops->pt_supported() ||
+ !intel_pt_validate_hw_cap(PT_CAP_cr3_filtering))
+ continue;
+ break;
+ case MSR_IA32_RTIT_OUTPUT_BASE:
+ case MSR_IA32_RTIT_OUTPUT_MASK:
+ if (!kvm_x86_ops->pt_supported() ||
+ (!intel_pt_validate_hw_cap(PT_CAP_topa_output) &&
+ !intel_pt_validate_hw_cap(PT_CAP_single_range_output)))
+ continue;
+ break;
+ case MSR_IA32_RTIT_ADDR0_A ... MSR_IA32_RTIT_ADDR3_B: {
+ if (!kvm_x86_ops->pt_supported() ||
+ msrs_to_save[i] - MSR_IA32_RTIT_ADDR0_A >=
+ intel_pt_validate_hw_cap(PT_CAP_num_address_ranges) * 2)
+ continue;
+ break;
+ }
default:
break;
}
--
1.8.3.1
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