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x86,kvm: remove KVM emulator get_fpu / put_fpu
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Now that get_fpu and put_fpu do nothing, because the scheduler will
automatically load and restore the guest FPU context for us while we
are in this code (deep inside the vcpu_run main loop), we can get rid
of the get_fpu and put_fpu hooks.

Signed-off-by: Rik van Riel <riel@redhat.com>
Suggested-by: David Hildenbrand <david@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
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Rik van Riel authored and Radim Krčmář committed Dec 5, 2017
1 parent f775b13 commit 6ab0b9f
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Showing 3 changed files with 0 additions and 36 deletions.
2 changes: 0 additions & 2 deletions arch/x86/include/asm/kvm_emulate.h
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Original file line number Diff line number Diff line change
Expand Up @@ -214,8 +214,6 @@ struct x86_emulate_ops {
void (*halt)(struct x86_emulate_ctxt *ctxt);
void (*wbinvd)(struct x86_emulate_ctxt *ctxt);
int (*fix_hypercall)(struct x86_emulate_ctxt *ctxt);
void (*get_fpu)(struct x86_emulate_ctxt *ctxt); /* disables preempt */
void (*put_fpu)(struct x86_emulate_ctxt *ctxt); /* reenables preempt */
int (*intercept)(struct x86_emulate_ctxt *ctxt,
struct x86_instruction_info *info,
enum x86_intercept_stage stage);
Expand Down
24 changes: 0 additions & 24 deletions arch/x86/kvm/emulate.c
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Original file line number Diff line number Diff line change
Expand Up @@ -1046,7 +1046,6 @@ static void fetch_register_operand(struct operand *op)

static void read_sse_reg(struct x86_emulate_ctxt *ctxt, sse128_t *data, int reg)
{
ctxt->ops->get_fpu(ctxt);
switch (reg) {
case 0: asm("movdqa %%xmm0, %0" : "=m"(*data)); break;
case 1: asm("movdqa %%xmm1, %0" : "=m"(*data)); break;
Expand All @@ -1068,13 +1067,11 @@ static void read_sse_reg(struct x86_emulate_ctxt *ctxt, sse128_t *data, int reg)
#endif
default: BUG();
}
ctxt->ops->put_fpu(ctxt);
}

static void write_sse_reg(struct x86_emulate_ctxt *ctxt, sse128_t *data,
int reg)
{
ctxt->ops->get_fpu(ctxt);
switch (reg) {
case 0: asm("movdqa %0, %%xmm0" : : "m"(*data)); break;
case 1: asm("movdqa %0, %%xmm1" : : "m"(*data)); break;
Expand All @@ -1096,12 +1093,10 @@ static void write_sse_reg(struct x86_emulate_ctxt *ctxt, sse128_t *data,
#endif
default: BUG();
}
ctxt->ops->put_fpu(ctxt);
}

static void read_mmx_reg(struct x86_emulate_ctxt *ctxt, u64 *data, int reg)
{
ctxt->ops->get_fpu(ctxt);
switch (reg) {
case 0: asm("movq %%mm0, %0" : "=m"(*data)); break;
case 1: asm("movq %%mm1, %0" : "=m"(*data)); break;
Expand All @@ -1113,12 +1108,10 @@ static void read_mmx_reg(struct x86_emulate_ctxt *ctxt, u64 *data, int reg)
case 7: asm("movq %%mm7, %0" : "=m"(*data)); break;
default: BUG();
}
ctxt->ops->put_fpu(ctxt);
}

static void write_mmx_reg(struct x86_emulate_ctxt *ctxt, u64 *data, int reg)
{
ctxt->ops->get_fpu(ctxt);
switch (reg) {
case 0: asm("movq %0, %%mm0" : : "m"(*data)); break;
case 1: asm("movq %0, %%mm1" : : "m"(*data)); break;
Expand All @@ -1130,17 +1123,14 @@ static void write_mmx_reg(struct x86_emulate_ctxt *ctxt, u64 *data, int reg)
case 7: asm("movq %0, %%mm7" : : "m"(*data)); break;
default: BUG();
}
ctxt->ops->put_fpu(ctxt);
}

static int em_fninit(struct x86_emulate_ctxt *ctxt)
{
if (ctxt->ops->get_cr(ctxt, 0) & (X86_CR0_TS | X86_CR0_EM))
return emulate_nm(ctxt);

ctxt->ops->get_fpu(ctxt);
asm volatile("fninit");
ctxt->ops->put_fpu(ctxt);
return X86EMUL_CONTINUE;
}

Expand All @@ -1151,9 +1141,7 @@ static int em_fnstcw(struct x86_emulate_ctxt *ctxt)
if (ctxt->ops->get_cr(ctxt, 0) & (X86_CR0_TS | X86_CR0_EM))
return emulate_nm(ctxt);

ctxt->ops->get_fpu(ctxt);
asm volatile("fnstcw %0": "+m"(fcw));
ctxt->ops->put_fpu(ctxt);

ctxt->dst.val = fcw;

Expand All @@ -1167,9 +1155,7 @@ static int em_fnstsw(struct x86_emulate_ctxt *ctxt)
if (ctxt->ops->get_cr(ctxt, 0) & (X86_CR0_TS | X86_CR0_EM))
return emulate_nm(ctxt);

ctxt->ops->get_fpu(ctxt);
asm volatile("fnstsw %0": "+m"(fsw));
ctxt->ops->put_fpu(ctxt);

ctxt->dst.val = fsw;

Expand Down Expand Up @@ -4001,12 +3987,8 @@ static int em_fxsave(struct x86_emulate_ctxt *ctxt)
if (rc != X86EMUL_CONTINUE)
return rc;

ctxt->ops->get_fpu(ctxt);

rc = asm_safe("fxsave %[fx]", , [fx] "+m"(fx_state));

ctxt->ops->put_fpu(ctxt);

if (rc != X86EMUL_CONTINUE)
return rc;

Expand Down Expand Up @@ -4049,8 +4031,6 @@ static int em_fxrstor(struct x86_emulate_ctxt *ctxt)
if (rc != X86EMUL_CONTINUE)
return rc;

ctxt->ops->get_fpu(ctxt);

if (size < __fxstate_size(16)) {
rc = fxregs_fixup(&fx_state, size);
if (rc != X86EMUL_CONTINUE)
Expand All @@ -4066,8 +4046,6 @@ static int em_fxrstor(struct x86_emulate_ctxt *ctxt)
rc = asm_safe("fxrstor %[fx]", : [fx] "m"(fx_state));

out:
ctxt->ops->put_fpu(ctxt);

return rc;
}

Expand Down Expand Up @@ -5317,9 +5295,7 @@ static int flush_pending_x87_faults(struct x86_emulate_ctxt *ctxt)
{
int rc;

ctxt->ops->get_fpu(ctxt);
rc = asm_safe("fwait");
ctxt->ops->put_fpu(ctxt);

if (unlikely(rc != X86EMUL_CONTINUE))
return emulate_exception(ctxt, MF_VECTOR, 0, false);
Expand Down
10 changes: 0 additions & 10 deletions arch/x86/kvm/x86.c
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Original file line number Diff line number Diff line change
Expand Up @@ -5251,14 +5251,6 @@ static void emulator_halt(struct x86_emulate_ctxt *ctxt)
emul_to_vcpu(ctxt)->arch.halt_request = 1;
}

static void emulator_get_fpu(struct x86_emulate_ctxt *ctxt)
{
}

static void emulator_put_fpu(struct x86_emulate_ctxt *ctxt)
{
}

static int emulator_intercept(struct x86_emulate_ctxt *ctxt,
struct x86_instruction_info *info,
enum x86_intercept_stage stage)
Expand Down Expand Up @@ -5336,8 +5328,6 @@ static const struct x86_emulate_ops emulate_ops = {
.halt = emulator_halt,
.wbinvd = emulator_wbinvd,
.fix_hypercall = emulator_fix_hypercall,
.get_fpu = emulator_get_fpu,
.put_fpu = emulator_put_fpu,
.intercept = emulator_intercept,
.get_cpuid = emulator_get_cpuid,
.set_nmi_mask = emulator_set_nmi_mask,
Expand Down

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