From: Arbel Moshe <arbel.moshe@xxxxxxxxxx> VMware exposes the following Pseudo PMCs: 0x10000: Physical host TSC 0x10001: Elapsed real time in ns 0x10002: Elapsed apparent time in ns For more info refer to: https://www.vmware.com/files/pdf/techpaper/Timekeeping-In-VirtualMachines.pdf VMware allows access to these Pseduo-PMCs even when read via RDPMC in Ring3 and CR4.PCE=0. Therefore, commit modifies x86 emulator to allow access to these PMCs in this situation. In addition, emulation of these PMCs were added to kvm_pmu_rdpmc(). Signed-off-by: Arbel Moshe <arbel.moshe@xxxxxxxxxx> Reviewed-by: Liran Alon <liran.alon@xxxxxxxxxx> Reviewed-by: Konrad Rzeszutek Wilk <konrad.wilk@xxxxxxxxxx> Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@xxxxxxxxxx> --- arch/x86/kvm/emulate.c | 8 ++++++++ arch/x86/kvm/pmu.c | 37 +++++++++++++++++++++++++++++++++++++ arch/x86/kvm/pmu.h | 6 ++++++ arch/x86/kvm/x86.c | 39 ++++++++++++++++++++++----------------- 4 files changed, 73 insertions(+), 17 deletions(-) diff --git a/arch/x86/kvm/emulate.c b/arch/x86/kvm/emulate.c index 8f4a75f4e8b9..ce5b2973fa18 100644 --- a/arch/x86/kvm/emulate.c +++ b/arch/x86/kvm/emulate.c @@ -29,6 +29,7 @@ #include "x86.h" #include "tss.h" #include "mmu.h" +#include "pmu.h" /* * Operand types @@ -4236,6 +4237,13 @@ static int check_rdpmc(struct x86_emulate_ctxt *ctxt) u64 cr4 = ctxt->ops->get_cr(ctxt, 4); u64 rcx = reg_read(ctxt, VCPU_REGS_RCX); + /* + * VMware allows access to these Pseduo-PMCs even when read via RDPMC + * in Ring3 when CR4.PCE=0. + */ + if (enable_vmware_backdoor && is_vmware_backdoor_pmc(rcx)) + return X86EMUL_CONTINUE; + if ((!(cr4 & X86_CR4_PCE) && ctxt->ops->cpl(ctxt)) || ctxt->ops->check_pmc(ctxt, rcx)) return emulate_gp(ctxt, 0); diff --git a/arch/x86/kvm/pmu.c b/arch/x86/kvm/pmu.c index 026db42a86c3..58ead7db71a3 100644 --- a/arch/x86/kvm/pmu.c +++ b/arch/x86/kvm/pmu.c @@ -244,12 +244,49 @@ int kvm_pmu_is_valid_msr_idx(struct kvm_vcpu *vcpu, unsigned idx) return kvm_x86_ops->pmu_ops->is_valid_msr_idx(vcpu, idx); } +bool is_vmware_backdoor_pmc(u32 pmc_idx) +{ + switch (pmc_idx) { + case VMWARE_BACKDOOR_PMC_HOST_TSC: + case VMWARE_BACKDOOR_PMC_REAL_TIME: + case VMWARE_BACKDOOR_PMC_APPARENT_TIME: + return true; + } + return false; +} + +static int kvm_pmu_rdpmc_vmware(struct kvm_vcpu *vcpu, unsigned idx, u64 *data) +{ + u64 ctr_val; + + switch (idx) { + case VMWARE_BACKDOOR_PMC_HOST_TSC: + ctr_val = rdtsc(); + break; + case VMWARE_BACKDOOR_PMC_REAL_TIME: + ctr_val = ktime_get_boot_ns(); + break; + case VMWARE_BACKDOOR_PMC_APPARENT_TIME: + ctr_val = ktime_get_boot_ns() + + vcpu->kvm->arch.kvmclock_offset; + break; + default: + return 1; + } + + *data = ctr_val; + return 0; +} + int kvm_pmu_rdpmc(struct kvm_vcpu *vcpu, unsigned idx, u64 *data) { bool fast_mode = idx & (1u << 31); struct kvm_pmc *pmc; u64 ctr_val; + if (is_vmware_backdoor_pmc(idx)) + return kvm_pmu_rdpmc_vmware(vcpu, idx, data); + pmc = kvm_x86_ops->pmu_ops->msr_idx_to_pmc(vcpu, idx); if (!pmc) return 1; diff --git a/arch/x86/kvm/pmu.h b/arch/x86/kvm/pmu.h index a9a62b9a73e2..ba8898e1a854 100644 --- a/arch/x86/kvm/pmu.h +++ b/arch/x86/kvm/pmu.h @@ -9,6 +9,10 @@ /* retrieve the 4 bits for EN and PMI out of IA32_FIXED_CTR_CTRL */ #define fixed_ctrl_field(ctrl_reg, idx) (((ctrl_reg) >> ((idx)*4)) & 0xf) +#define VMWARE_BACKDOOR_PMC_HOST_TSC 0x10000 +#define VMWARE_BACKDOOR_PMC_REAL_TIME 0x10001 +#define VMWARE_BACKDOOR_PMC_APPARENT_TIME 0x10002 + struct kvm_event_hw_type_mapping { u8 eventsel; u8 unit_mask; @@ -114,6 +118,8 @@ static inline struct kvm_pmc *get_fixed_pmc(struct kvm_pmu *pmu, u32 msr) void kvm_pmu_init(struct kvm_vcpu *vcpu); void kvm_pmu_destroy(struct kvm_vcpu *vcpu); +bool is_vmware_backdoor_pmc(u32 pmc_idx); + extern struct kvm_pmu_ops intel_pmu_ops; extern struct kvm_pmu_ops amd_pmu_ops; #endif /* __KVM_X86_PMU_H */ diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index db040ada2cde..8c6827b21840 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -5687,23 +5687,28 @@ static bool kvm_vcpu_check_breakpoint(struct kvm_vcpu *vcpu, int *r) static bool is_vmware_backdoor_opcode(struct x86_emulate_ctxt *ctxt) { - if (ctxt->opcode_len != 1) - return false; - - switch (ctxt->b) { - case 0xe4: /* IN */ - case 0xe5: - case 0xec: - case 0xed: - case 0xe6: /* OUT */ - case 0xe7: - case 0xee: - case 0xef: - case 0x6c: /* INS */ - case 0x6d: - case 0x6e: /* OUTS */ - case 0x6f: - return true; + switch (ctxt->opcode_len) { + case 1: + switch (ctxt->b) { + case 0xe4: /* IN */ + case 0xe5: + case 0xec: + case 0xed: + case 0xe6: /* OUT */ + case 0xe7: + case 0xee: + case 0xef: + case 0x6c: /* INS */ + case 0x6d: + case 0x6e: /* OUTS */ + case 0x6f: + return true; + } + case 2: + switch (ctxt->b) { + case 0x33: /* RDPMC */ + return true; + } } return false; -- 1.9.1
