KVM: x86: Update vPMCs when retiring branch instructions

When KVM retires a guest branch instruction through emulation,
increment any vPMCs that are configured to monitor "branch
instructions retired," and update the sample period of those counters
so that they will overflow at the right time.

Signed-off-by: Eric Hankland <ehankland@google.com>
[jmattson:
  - Split the code to increment "branch instructions retired" into a
    separate commit.
  - Moved/consolidated the calls to kvm_pmu_trigger_event() in the
    emulation of VMLAUNCH/VMRESUME to accommodate the evolution of
    that code.
]
Fixes: f5132b01386b ("KVM: Expose a version 2 architectural PMU to a guests")
Signed-off-by: Jim Mattson <jmattson@google.com>
Message-Id: <20211130074221.93635-7-likexu@tencent.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

diff --git a/arch/x86/kvm/emulate.c b/arch/x86/kvm/emulate.c
index 28b1a4e..166a145 100644 (file)
--- a/arch/x86/kvm/emulate.c
+++ b/arch/x86/kvm/emulate.c
@@ -175,6 +175,7 @@
 #define No16       ((u64)1 << 53)  /* No 16 bit operand */
 #define IncSP       ((u64)1 << 54)  /* SP is incremented before ModRM calc */
 #define TwoMemOp    ((u64)1 << 55)  /* Instruction has two memory operand */
+#define IsBranch    ((u64)1 << 56)  /* Instruction is considered a branch. */
 
 #define DstXacc     (DstAccLo | SrcAccHi | SrcWrite)
 
@@ -191,8 +192,9 @@
 #define FASTOP_SIZE 8
 
 struct opcode {
-       u64 flags : 56;
-       u64 intercept : 8;
+       u64 flags;
+       u8 intercept;
+       u8 pad[7];
        union {
                int (*execute)(struct x86_emulate_ctxt *ctxt);
                const struct opcode *group;
@@ -4364,10 +4366,10 @@ static const struct opcode group4[] = {
 static const struct opcode group5[] = {
        F(DstMem | SrcNone | Lock,              em_inc),
        F(DstMem | SrcNone | Lock,              em_dec),
-       I(SrcMem | NearBranch,                  em_call_near_abs),
-       I(SrcMemFAddr | ImplicitOps,            em_call_far),
-       I(SrcMem | NearBranch,                  em_jmp_abs),
-       I(SrcMemFAddr | ImplicitOps,            em_jmp_far),
+       I(SrcMem | NearBranch | IsBranch,       em_call_near_abs),
+       I(SrcMemFAddr | ImplicitOps | IsBranch, em_call_far),
+       I(SrcMem | NearBranch | IsBranch,       em_jmp_abs),
+       I(SrcMemFAddr | ImplicitOps | IsBranch, em_jmp_far),
        I(SrcMem | Stack | TwoMemOp,            em_push), D(Undefined),
 };
 
@@ -4577,7 +4579,7 @@ static const struct opcode opcode_table[256] = {
        I2bvIP(DstDI | SrcDX | Mov | String | Unaligned, em_in, ins, check_perm_in), /* insb, insw/insd */
        I2bvIP(SrcSI | DstDX | String, em_out, outs, check_perm_out), /* outsb, outsw/outsd */
        /* 0x70 - 0x7F */
-       X16(D(SrcImmByte | NearBranch)),
+       X16(D(SrcImmByte | NearBranch | IsBranch)),
        /* 0x80 - 0x87 */
        G(ByteOp | DstMem | SrcImm, group1),
        G(DstMem | SrcImm, group1),
@@ -4596,7 +4598,7 @@ static const struct opcode opcode_table[256] = {
        DI(SrcAcc | DstReg, pause), X7(D(SrcAcc | DstReg)),
        /* 0x98 - 0x9F */
        D(DstAcc | SrcNone), I(ImplicitOps | SrcAcc, em_cwd),
-       I(SrcImmFAddr | No64, em_call_far), N,
+       I(SrcImmFAddr | No64 | IsBranch, em_call_far), N,
        II(ImplicitOps | Stack, em_pushf, pushf),
        II(ImplicitOps | Stack, em_popf, popf),
        I(ImplicitOps, em_sahf), I(ImplicitOps, em_lahf),
@@ -4616,17 +4618,19 @@ static const struct opcode opcode_table[256] = {
        X8(I(DstReg | SrcImm64 | Mov, em_mov)),
        /* 0xC0 - 0xC7 */
        G(ByteOp | Src2ImmByte, group2), G(Src2ImmByte, group2),
-       I(ImplicitOps | NearBranch | SrcImmU16, em_ret_near_imm),
-       I(ImplicitOps | NearBranch, em_ret),
+       I(ImplicitOps | NearBranch | SrcImmU16 | IsBranch, em_ret_near_imm),
+       I(ImplicitOps | NearBranch | IsBranch, em_ret),
        I(DstReg | SrcMemFAddr | ModRM | No64 | Src2ES, em_lseg),
        I(DstReg | SrcMemFAddr | ModRM | No64 | Src2DS, em_lseg),
        G(ByteOp, group11), G(0, group11),
        /* 0xC8 - 0xCF */
-       I(Stack | SrcImmU16 | Src2ImmByte, em_enter), I(Stack, em_leave),
-       I(ImplicitOps | SrcImmU16, em_ret_far_imm),
-       I(ImplicitOps, em_ret_far),
-       D(ImplicitOps), DI(SrcImmByte, intn),
-       D(ImplicitOps | No64), II(ImplicitOps, em_iret, iret),
+       I(Stack | SrcImmU16 | Src2ImmByte | IsBranch, em_enter),
+       I(Stack | IsBranch, em_leave),
+       I(ImplicitOps | SrcImmU16 | IsBranch, em_ret_far_imm),
+       I(ImplicitOps | IsBranch, em_ret_far),
+       D(ImplicitOps | IsBranch), DI(SrcImmByte | IsBranch, intn),
+       D(ImplicitOps | No64 | IsBranch),
+       II(ImplicitOps | IsBranch, em_iret, iret),
        /* 0xD0 - 0xD7 */
        G(Src2One | ByteOp, group2), G(Src2One, group2),
        G(Src2CL | ByteOp, group2), G(Src2CL, group2),
@@ -4637,14 +4641,15 @@ static const struct opcode opcode_table[256] = {
        /* 0xD8 - 0xDF */
        N, E(0, &escape_d9), N, E(0, &escape_db), N, E(0, &escape_dd), N, N,
        /* 0xE0 - 0xE7 */
-       X3(I(SrcImmByte | NearBranch, em_loop)),
-       I(SrcImmByte | NearBranch, em_jcxz),
+       X3(I(SrcImmByte | NearBranch | IsBranch, em_loop)),
+       I(SrcImmByte | NearBranch | IsBranch, em_jcxz),
        I2bvIP(SrcImmUByte | DstAcc, em_in,  in,  check_perm_in),
        I2bvIP(SrcAcc | DstImmUByte, em_out, out, check_perm_out),
        /* 0xE8 - 0xEF */
-       I(SrcImm | NearBranch, em_call), D(SrcImm | ImplicitOps | NearBranch),
-       I(SrcImmFAddr | No64, em_jmp_far),
-       D(SrcImmByte | ImplicitOps | NearBranch),
+       I(SrcImm | NearBranch | IsBranch, em_call),
+       D(SrcImm | ImplicitOps | NearBranch | IsBranch),
+       I(SrcImmFAddr | No64 | IsBranch, em_jmp_far),
+       D(SrcImmByte | ImplicitOps | NearBranch | IsBranch),
        I2bvIP(SrcDX | DstAcc, em_in,  in,  check_perm_in),
        I2bvIP(SrcAcc | DstDX, em_out, out, check_perm_out),
        /* 0xF0 - 0xF7 */
@@ -4660,7 +4665,7 @@ static const struct opcode opcode_table[256] = {
 static const struct opcode twobyte_table[256] = {
        /* 0x00 - 0x0F */
        G(0, group6), GD(0, &group7), N, N,
-       N, I(ImplicitOps | EmulateOnUD, em_syscall),
+       N, I(ImplicitOps | EmulateOnUD | IsBranch, em_syscall),
        II(ImplicitOps | Priv, em_clts, clts), N,
        DI(ImplicitOps | Priv, invd), DI(ImplicitOps | Priv, wbinvd), N, N,
        N, D(ImplicitOps | ModRM | SrcMem | NoAccess), N, N,
@@ -4691,8 +4696,8 @@ static const struct opcode twobyte_table[256] = {
        IIP(ImplicitOps, em_rdtsc, rdtsc, check_rdtsc),
        II(ImplicitOps | Priv, em_rdmsr, rdmsr),
        IIP(ImplicitOps, em_rdpmc, rdpmc, check_rdpmc),
-       I(ImplicitOps | EmulateOnUD, em_sysenter),
-       I(ImplicitOps | Priv | EmulateOnUD, em_sysexit),
+       I(ImplicitOps | EmulateOnUD | IsBranch, em_sysenter),
+       I(ImplicitOps | Priv | EmulateOnUD | IsBranch, em_sysexit),
        N, N,
        N, N, N, N, N, N, N, N,
        /* 0x40 - 0x4F */
@@ -4710,7 +4715,7 @@ static const struct opcode twobyte_table[256] = {
        N, N, N, N,
        N, N, N, GP(SrcReg | DstMem | ModRM | Mov, &pfx_0f_6f_0f_7f),
        /* 0x80 - 0x8F */
-       X16(D(SrcImm | NearBranch)),
+       X16(D(SrcImm | NearBranch | IsBranch)),
        /* 0x90 - 0x9F */
        X16(D(ByteOp | DstMem | SrcNone | ModRM| Mov)),
        /* 0xA0 - 0xA7 */
@@ -5224,6 +5229,8 @@ done_prefixes:
                ctxt->d |= opcode.flags;
        }
 
+       ctxt->is_branch = opcode.flags & IsBranch;
+
        /* Unrecognised? */
        if (ctxt->d == 0)
                return EMULATION_FAILED;

diff --git a/arch/x86/kvm/kvm_emulate.h b/arch/x86/kvm/kvm_emulate.h
index 68b4202..39eded2 100644 (file)
--- a/arch/x86/kvm/kvm_emulate.h
+++ b/arch/x86/kvm/kvm_emulate.h
@@ -369,6 +369,7 @@ struct x86_emulate_ctxt {
        struct fetch_cache fetch;
        struct read_cache io_read;
        struct read_cache mem_read;
+       bool is_branch;
 };
 
 /* Repeat String Operation Prefix */

diff --git a/arch/x86/kvm/vmx/nested.c b/arch/x86/kvm/vmx/nested.c
index d07a7fa..f235f77 100644 (file)
--- a/arch/x86/kvm/vmx/nested.c
+++ b/arch/x86/kvm/vmx/nested.c
@@ -3526,10 +3526,13 @@ static int nested_vmx_run(struct kvm_vcpu *vcpu, bool launch)
        if (evmptrld_status == EVMPTRLD_ERROR) {
                kvm_queue_exception(vcpu, UD_VECTOR);
                return 1;
-       } else if (CC(evmptrld_status == EVMPTRLD_VMFAIL)) {
-               return nested_vmx_failInvalid(vcpu);
        }
 
+       kvm_pmu_trigger_event(vcpu, PERF_COUNT_HW_BRANCH_INSTRUCTIONS);
+
+       if (CC(evmptrld_status == EVMPTRLD_VMFAIL))
+               return nested_vmx_failInvalid(vcpu);
+
        if (CC(!evmptr_is_valid(vmx->nested.hv_evmcs_vmptr) &&
               vmx->nested.current_vmptr == INVALID_GPA))
                return nested_vmx_failInvalid(vcpu);

diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 4fbde3a..42bde45 100644 (file)
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -8255,6 +8255,8 @@ writeback:
                if (!ctxt->have_exception ||
                    exception_type(ctxt->exception.vector) == EXCPT_TRAP) {
                        kvm_pmu_trigger_event(vcpu, PERF_COUNT_HW_INSTRUCTIONS);
+                       if (ctxt->is_branch)
+                               kvm_pmu_trigger_event(vcpu, PERF_COUNT_HW_BRANCH_INSTRUCTIONS);
                        kvm_rip_write(vcpu, ctxt->eip);
                        if (r && (ctxt->tf || (vcpu->guest_debug & KVM_GUESTDBG_SINGLESTEP)))
                                r = kvm_vcpu_do_singlestep(vcpu);