[PATCH v2 4/4] KVM: VMX: details of LBR virtualization implementation
From: Jian Zhou
Date: Fri Oct 23 2015 - 05:18:07 EST
Using msr intercept bitmap and arrays(save/restore LBR MSRs)
in kvm_vcpu_arch struct to support LBR virtualization.
Add a parameter of kvm_intel module to permanently disable
LBRV.
Reorgnized the table of supported CPUs, LBRV can be enabled
or not according to the guest CPUID.
Signed-off-by: Jian Zhou <jianjay.zhou@xxxxxxxxxx>
Signed-off-by: Stephen He <herongguang.he@xxxxxxxxxx>
---
arch/x86/kvm/vmx.c | 245 +++++++++++++++++++++++++++++++++++++++++++++++++++++
1 file changed, 245 insertions(+)
diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
index 6a8bc64..3ab890d 100644
--- a/arch/x86/kvm/vmx.c
+++ b/arch/x86/kvm/vmx.c
@@ -90,6 +90,9 @@ module_param(fasteoi, bool, S_IRUGO);
static bool __read_mostly enable_apicv = 1;
module_param(enable_apicv, bool, S_IRUGO);
+static bool __read_mostly lbrv = 1;
+module_param(lbrv, bool, S_IRUGO);
+
static bool __read_mostly enable_shadow_vmcs = 1;
module_param_named(enable_shadow_vmcs, enable_shadow_vmcs, bool, S_IRUGO);
/*
@@ -4323,6 +4326,21 @@ static void vmx_disable_intercept_msr_write_x2apic(u32 msr)
msr, MSR_TYPE_W);
}
+static void vmx_disable_intercept_guest_msr(struct kvm_vcpu *vcpu, u32 msr)
+{
+ if (irqchip_in_kernel(vcpu->kvm) &&
+ apic_x2apic_mode(vcpu->arch.apic)) {
+ vmx_disable_intercept_msr_read_x2apic(msr);
+ vmx_disable_intercept_msr_write_x2apic(msr);
+ }
+ else {
+ if (is_long_mode(vcpu))
+ vmx_disable_intercept_for_msr(msr, true);
+ else
+ vmx_disable_intercept_for_msr(msr, false);
+ }
+}
+
static int vmx_vm_has_apicv(struct kvm *kvm)
{
return enable_apicv && irqchip_in_kernel(kvm);
@@ -6037,6 +6055,13 @@ static __init int hardware_setup(void)
kvm_x86_ops->sync_pir_to_irr = vmx_sync_pir_to_irr_dummy;
}
+ if (!lbrv) {
+ kvm_x86_ops->set_debugctlmsr = NULL;
+ kvm_x86_ops->get_debugctlmsr = NULL;
+ kvm_x86_ops->set_lbr_msr = NULL;
+ kvm_x86_ops->get_lbr_msr = NULL;
+ }
+
vmx_disable_intercept_for_msr(MSR_FS_BASE, false);
vmx_disable_intercept_for_msr(MSR_GS_BASE, false);
vmx_disable_intercept_for_msr(MSR_KERNEL_GS_BASE, true);
@@ -8258,6 +8283,215 @@ static void atomic_switch_perf_msrs(struct vcpu_vmx *vmx)
msrs[i].host);
}
+struct lbr_info {
+ u32 base;
+ u8 count;
+} pentium4_lbr[] = {
+ { MSR_LBR_SELECT, 1 },
+ { MSR_PENTIUM4_LER_FROM_LIP, 1 },
+ { MSR_PENTIUM4_LER_TO_LIP, 1 },
+ { MSR_PENTIUM4_LBR_TOS, 1 },
+ { MSR_LBR_PENTIUM4_FROM, SIZE_PENTIUM4_LBR_STACK },
+ { MSR_LBR_PENTIUM4_TO, SIZE_PENTIUM4_LBR_STACK },
+ { 0, 0 }
+}, core2_lbr[] = {
+ { MSR_LBR_SELECT, 1 },
+ { MSR_IA32_LASTINTFROMIP, 1 },
+ { MSR_IA32_LASTINTTOIP, 1 },
+ { MSR_LBR_TOS, 1 },
+ { MSR_LBR_CORE2_FROM, SIZE_CORE2_LBR_STACK },
+ { MSR_LBR_CORE2_TO, SIZE_CORE2_LBR_STACK },
+ { 0, 0 }
+}, atom_lbr[] = {
+ { MSR_LBR_SELECT, 1 },
+ { MSR_IA32_LASTINTFROMIP, 1 },
+ { MSR_IA32_LASTINTTOIP, 1 },
+ { MSR_LBR_TOS, 1 },
+ { MSR_LBR_ATOM_FROM, SIZE_ATOM_LBR_STACK },
+ { MSR_LBR_ATOM_TO, SIZE_ATOM_LBR_STACK },
+ { 0, 0 }
+}, nehalem_lbr[] = {
+ { MSR_LBR_SELECT, 1 },
+ { MSR_IA32_LASTINTFROMIP, 1 },
+ { MSR_IA32_LASTINTTOIP, 1 },
+ { MSR_LBR_TOS, 1 },
+ { MSR_LBR_NHM_FROM, SIZE_NHM_LBR_STACK },
+ { MSR_LBR_NHM_TO, SIZE_NHM_LBR_STACK },
+ { 0, 0 }
+}, skylake_lbr[] = {
+ { MSR_LBR_SELECT, 1 },
+ { MSR_IA32_LASTINTFROMIP, 1 },
+ { MSR_IA32_LASTINTTOIP, 1 },
+ { MSR_LBR_TOS, 1 },
+ { MSR_LBR_SKYLAKE_FROM, SIZE_SKYLAKE_LBR_STACK },
+ { MSR_LBR_SKYLAKE_TO, SIZE_SKYLAKE_LBR_STACK },
+ { 0, 0}
+};
+
+static const struct lbr_info *last_branch_msr_get(struct kvm_vcpu *vcpu)
+{
+ struct kvm_cpuid_entry2 *best = kvm_find_cpuid_entry(vcpu, 1, 0);
+ u32 eax = best->eax;
+ u8 family = (eax >> 8) & 0xf;
+ u8 model = (eax >> 4) & 0xf;
+
+ if (family == 15)
+ family += (eax >> 20) & 0xff;
+ if (family >= 6)
+ model += ((eax >> 16) & 0xf) << 4;
+
+ if (family == 6)
+ {
+ switch (model)
+ {
+ case 15: /* 65nm Core2 "Merom" */
+ case 22: /* 65nm Core2 "Merom-L" */
+ case 23: /* 45nm Core2 "Penryn" */
+ case 29: /* 45nm Core2 "Dunnington (MP) */
+ return core2_lbr;
+ break;
+ case 28: /* 45nm Atom "Pineview" */
+ case 38: /* 45nm Atom "Lincroft" */
+ case 39: /* 32nm Atom "Penwell" */
+ case 53: /* 32nm Atom "Cloverview" */
+ case 54: /* 32nm Atom "Cedarview" */
+ case 55: /* 22nm Atom "Silvermont" */
+ case 76: /* 14nm Atom "Airmont" */
+ case 77: /* 22nm Atom "Silvermont Avoton/Rangely" */
+ return atom_lbr;
+ break;
+ case 30: /* 45nm Nehalem */
+ case 26: /* 45nm Nehalem-EP */
+ case 46: /* 45nm Nehalem-EX */
+ case 37: /* 32nm Westmere */
+ case 44: /* 32nm Westmere-EP */
+ case 47: /* 32nm Westmere-EX */
+ case 42: /* 32nm SandyBridge */
+ case 45: /* 32nm SandyBridge-E/EN/EP */
+ case 58: /* 22nm IvyBridge */
+ case 62: /* 22nm IvyBridge-EP/EX */
+ case 60: /* 22nm Haswell Core */
+ case 63: /* 22nm Haswell Server */
+ case 69: /* 22nm Haswell ULT */
+ case 70: /* 22nm Haswell + GT3e */
+ case 61: /* 14nm Broadwell Core-M */
+ case 86: /* 14nm Broadwell Xeon D */
+ case 71: /* 14nm Broadwell + GT3e */
+ case 79: /* 14nm Broadwell Server */
+ return nehalem_lbr;
+ break;
+ case 78: /* 14nm Skylake Mobile */
+ case 94: /* 14nm Skylake Desktop */
+ return skylake_lbr;
+ break;
+ }
+ }
+ if (family == 15) {
+ switch (model)
+ {
+ /* Pentium4/Xeon(based on NetBurst)*/
+ case 3:
+ case 4:
+ case 6:
+ return pentium4_lbr;
+ break;
+ }
+ }
+
+ return NULL;
+}
+
+static int vmx_enable_lbrv(struct kvm_vcpu *vcpu)
+{
+ int i;
+ const struct lbr_info *lbr = last_branch_msr_get(vcpu);
+ struct lbr_msr *m = &(vcpu->arch.lbr_msr);
+
+ if (lbr == NULL)
+ return 1;
+
+ if (vcpu->arch.lbr_used) {
+ vcpu->arch.lbr_status = 1;
+ return 0;
+ }
+
+ for (; lbr->count; lbr++)
+ for (i = 0; (i < lbr->count); i++) {
+ m->host[m->nr].index = lbr->base + i;
+ m->host[m->nr].data = 0;
+ m->guest[m->nr].index = lbr->base + i;
+ m->guest[m->nr].data = 0;
+ m->nr++;
+
+ vmx_disable_intercept_guest_msr(vcpu, lbr->base + i);
+ }
+
+ vcpu->arch.lbr_status = 1;
+ vcpu->arch.lbr_used = 1;
+
+ return 0;
+}
+
+static int vmx_set_debugctlmsr(struct kvm_vcpu *vcpu, u64 value)
+{
+ if (value & DEBUGCTLMSR_LBR) {
+ if (vmx_enable_lbrv(vcpu))
+ return 1;
+ } else
+ vcpu->arch.lbr_status = 0;
+
+ vmcs_write64(GUEST_IA32_DEBUGCTL, value);
+
+ return 0;
+}
+
+static u64 vmx_get_debugctlmsr(void)
+{
+ return vmcs_read64(GUEST_IA32_DEBUGCTL);
+}
+
+static void vmx_set_lbr_msr(struct kvm_vcpu *vcpu, u32 msr, u64 data)
+{
+ unsigned i;
+ struct lbr_msr *m = &(vcpu->arch.lbr_msr);
+
+ for (i = 0; i < m->nr; ++i)
+ if (m->guest[i].index == msr)
+ m->guest[i].data = data;
+}
+
+static u64 vmx_get_lbr_msr(struct kvm_vcpu *vcpu, u32 msr)
+{
+ unsigned i;
+ struct lbr_msr *m = &(vcpu->arch.lbr_msr);
+
+ for (i = 0; i < m->nr; ++i)
+ if (m->guest[i].index == msr)
+ break;
+
+ if (i < m->nr)
+ return m->guest[i].data;
+ else
+ return 0;
+}
+
+static void switch_lbr_msrs(struct kvm_vcpu *vcpu, int vm_exit)
+{
+ int i;
+ struct lbr_msr *m = &(vcpu->arch.lbr_msr);
+
+ for (i = 0; i < m->nr; ++i) {
+ if (vm_exit) {
+ rdmsrl(m->guest[i].index, m->guest[i].data);
+ wrmsrl(m->host[i].index, m->host[i].data);
+ }
+ else {
+ rdmsrl(m->host[i].index, m->host[i].data);
+ wrmsrl(m->guest[i].index, m->guest[i].data);
+ }
+ }
+}
+
static void __noclone vmx_vcpu_run(struct kvm_vcpu *vcpu)
{
struct vcpu_vmx *vmx = to_vmx(vcpu);
@@ -8304,6 +8538,9 @@ static void __noclone vmx_vcpu_run(struct kvm_vcpu *vcpu)
atomic_switch_perf_msrs(vmx);
debugctlmsr = get_debugctlmsr();
+ if (vcpu->arch.lbr_used)
+ switch_lbr_msrs(vcpu, 0);
+
vmx->__launched = vmx->loaded_vmcs->launched;
asm(
/* Store host registers */
@@ -8410,6 +8647,9 @@ static void __noclone vmx_vcpu_run(struct kvm_vcpu *vcpu)
#endif
);
+ if (vcpu->arch.lbr_used)
+ switch_lbr_msrs(vcpu, 1);
+
/* MSR_IA32_DEBUGCTLMSR is zeroed on vmexit. Restore it if needed */
if (debugctlmsr)
update_debugctlmsr(debugctlmsr);
@@ -10395,6 +10635,11 @@ static struct kvm_x86_ops vmx_x86_ops = {
.enable_log_dirty_pt_masked = vmx_enable_log_dirty_pt_masked,
.pmu_ops = &intel_pmu_ops,
+
+ .set_debugctlmsr = vmx_set_debugctlmsr,
+ .get_debugctlmsr = vmx_get_debugctlmsr,
+ .set_lbr_msr = vmx_set_lbr_msr,
+ .get_lbr_msr = vmx_get_lbr_msr,
};
static int __init vmx_init(void)
--
1.7.12.4
--
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