[PATCH v2 3/4] KVM: X86: Migration is supported

From: Jian Zhou
Date: Fri Oct 23 2015 - 04:51:22 EST


Supported bits of MSR_IA32_DEBUGCTLMSR are DEBUGCTLMSR_LBR(bit 0),
DEBUGCTLMSR_BTF(bit 1) and DEBUGCTLMSR_FREEZE_LBRS_ON_PMI(bit 11).
Qemu can get/set contents of LBR MSRs and LBR status in order to
support migration.

Signed-off-by: Jian Zhou <jianjay.zhou@xxxxxxxxxx>
Signed-off-by: Stephen He <herongguang.he@xxxxxxxxxx>
---
arch/x86/kvm/x86.c | 88 +++++++++++++++++++++++++++++++++++++++++++++++-------
1 file changed, 77 insertions(+), 11 deletions(-)

diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 9a9a198..a3c72db 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -136,6 +136,8 @@ struct kvm_shared_msrs {
static struct kvm_shared_msrs_global __read_mostly shared_msrs_global;
static struct kvm_shared_msrs __percpu *shared_msrs;

+#define MSR_LBR_STATUS 0xd6
+
struct kvm_stats_debugfs_item debugfs_entries[] = {
{ "pf_fixed", VCPU_STAT(pf_fixed) },
{ "pf_guest", VCPU_STAT(pf_guest) },
@@ -1917,6 +1919,7 @@ int kvm_set_msr_common(struct kvm_vcpu *vcpu, struct msr_data *msr_info)
bool pr = false;
u32 msr = msr_info->index;
u64 data = msr_info->data;
+ u64 supported = 0;

switch (msr) {
case MSR_AMD64_NB_CFG:
@@ -1948,16 +1951,25 @@ int kvm_set_msr_common(struct kvm_vcpu *vcpu, struct msr_data *msr_info)
}
break;
case MSR_IA32_DEBUGCTLMSR:
- if (!data) {
- /* We support the non-activated case already */
- break;
- } else if (data & ~(DEBUGCTLMSR_LBR | DEBUGCTLMSR_BTF)) {
- /* Values other than LBR and BTF are vendor-specific,
- thus reserved and should throw a #GP */
+ supported = DEBUGCTLMSR_LBR | DEBUGCTLMSR_BTF |
+ DEBUGCTLMSR_FREEZE_LBRS_ON_PMI;
+
+ if (data & ~supported) {
+ /*
+ * Values other than LBR/BTF/FREEZE_LBRS_ON_PMI
+ * are not supported, thus reserved and should throw a #GP
+ */
+ vcpu_unimpl(vcpu, "%s: MSR_IA32_DEBUGCTLMSR 0x%llx, nop\n",
+ __func__, data);
return 1;
}
- vcpu_unimpl(vcpu, "%s: MSR_IA32_DEBUGCTLMSR 0x%llx, nop\n",
- __func__, data);
+ if (kvm_x86_ops->set_debugctlmsr) {
+ if (kvm_x86_ops->set_debugctlmsr(vcpu, data))
+ return 1;
+ }
+ else
+ return 1;
+
break;
case 0x200 ... 0x2ff:
return kvm_mtrr_set_msr(vcpu, msr, data);
@@ -2078,6 +2090,33 @@ int kvm_set_msr_common(struct kvm_vcpu *vcpu, struct msr_data *msr_info)
vcpu_unimpl(vcpu, "disabled perfctr wrmsr: "
"0x%x data 0x%llx\n", msr, data);
break;
+ case MSR_LBR_STATUS:
+ if (kvm_x86_ops->set_debugctlmsr) {
+ vcpu->arch.lbr_status = (data == 0) ? 0 : 1;
+ if (data)
+ kvm_x86_ops->set_debugctlmsr(vcpu,
+ DEBUGCTLMSR_LBR | DEBUGCTLMSR_FREEZE_LBRS_ON_PMI);
+ } else
+ vcpu_unimpl(vcpu, "lbr is disabled, ignored wrmsr: "
+ "0x%x data 0x%llx\n", msr, data);
+ break;
+ case MSR_LBR_SELECT:
+ case MSR_LBR_TOS:
+ case MSR_PENTIUM4_LER_FROM_LIP:
+ case MSR_PENTIUM4_LER_TO_LIP:
+ case MSR_PENTIUM4_LBR_TOS:
+ case MSR_IA32_LASTINTFROMIP:
+ case MSR_IA32_LASTINTTOIP:
+ case MSR_LBR_CORE2_FROM ... MSR_LBR_CORE2_FROM + 0x7:
+ case MSR_LBR_CORE2_TO ... MSR_LBR_CORE2_TO + 0x7:
+ case MSR_LBR_NHM_FROM ... MSR_LBR_NHM_FROM + 0x1f:
+ case MSR_LBR_NHM_TO ... MSR_LBR_NHM_TO + 0x1f:
+ if (kvm_x86_ops->set_lbr_msr)
+ kvm_x86_ops->set_lbr_msr(vcpu, msr, data);
+ else
+ vcpu_unimpl(vcpu, "lbr is disabled, ignored wrmsr: "
+ "0x%x data 0x%llx\n", msr, data);
+ break;
case MSR_K7_CLK_CTL:
/*
* Ignore all writes to this no longer documented MSR.
@@ -2178,13 +2217,16 @@ static int get_msr_mce(struct kvm_vcpu *vcpu, u32 msr, u64 *pdata)
int kvm_get_msr_common(struct kvm_vcpu *vcpu, struct msr_data *msr_info)
{
switch (msr_info->index) {
+ case MSR_IA32_DEBUGCTLMSR:
+ if (kvm_x86_ops->get_debugctlmsr)
+ msr_info->data = kvm_x86_ops->get_debugctlmsr();
+ else
+ msr_info->data = 0;
+ break;
case MSR_IA32_PLATFORM_ID:
case MSR_IA32_EBL_CR_POWERON:
- case MSR_IA32_DEBUGCTLMSR:
case MSR_IA32_LASTBRANCHFROMIP:
case MSR_IA32_LASTBRANCHTOIP:
- case MSR_IA32_LASTINTFROMIP:
- case MSR_IA32_LASTINTTOIP:
case MSR_K8_SYSCFG:
case MSR_K8_TSEG_ADDR:
case MSR_K8_TSEG_MASK:
@@ -2204,6 +2246,26 @@ int kvm_get_msr_common(struct kvm_vcpu *vcpu, struct msr_data *msr_info)
return kvm_pmu_get_msr(vcpu, msr_info->index, &msr_info->data);
msr_info->data = 0;
break;
+ case MSR_LBR_STATUS:
+ msr_info->data = vcpu->arch.lbr_status;
+ break;
+ case MSR_LBR_SELECT:
+ case MSR_LBR_TOS:
+ case MSR_PENTIUM4_LER_FROM_LIP:
+ case MSR_PENTIUM4_LER_TO_LIP:
+ case MSR_PENTIUM4_LBR_TOS:
+ case MSR_IA32_LASTINTFROMIP:
+ case MSR_IA32_LASTINTTOIP:
+ case MSR_LBR_CORE2_FROM ... MSR_LBR_CORE2_FROM + 0x7:
+ case MSR_LBR_CORE2_TO ... MSR_LBR_CORE2_TO + 0x7:
+ case MSR_LBR_SKYLAKE_FROM ... MSR_LBR_SKYLAKE_FROM + 0x1f:
+ case MSR_LBR_SKYLAKE_TO ... MSR_LBR_SKYLAKE_TO + 0x1f:
+ if (kvm_x86_ops->get_lbr_msr)
+ msr_info->data = kvm_x86_ops->get_lbr_msr(vcpu,
+ msr_info->index);
+ else
+ msr_info->data = 0;
+ break;
case MSR_IA32_UCODE_REV:
msr_info->data = 0x100000000ULL;
break;
@@ -7376,6 +7438,10 @@ int kvm_arch_vcpu_init(struct kvm_vcpu *vcpu)
kvm_async_pf_hash_reset(vcpu);
kvm_pmu_init(vcpu);

+ vcpu->arch.lbr_status = 0;
+ vcpu->arch.lbr_used = 0;
+ vcpu->arch.lbr_msr.nr = 0;
+
return 0;

fail_free_mce_banks:
--
1.7.12.4


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