[PATCH v2 1/4] KVM: x86: Move FPU register accessors into fpu.h

Siddharth Chandrasekaran
2021-04-12T17:02:37Z

Hyper-v XMM fast hypercalls use XMM registers to pass input/output
parameters. To access these, hyperv.c can reuse some FPU register
accessors defined in emulator.c. Move them to a common location so both
can access them.

While at it, reorder the parameters of these accessor methods to make
them more readable.

Cc: Alexander Graf <graf@amazon.com>
Cc: Evgeny Iakovlev <eyakovl@amazon.de>
Signed-off-by: Siddharth Chandrasekaran <sidcha@amazon.de>
---
arch/x86/kvm/emulate.c | 138 ++++++----------------------------------
arch/x86/kvm/fpu.h | 140 +++++++++++++++++++++++++++++++++++++++++
2 files changed, 158 insertions(+), 120 deletions(-)
create mode 100644 arch/x86/kvm/fpu.h

diff --git a/arch/x86/kvm/emulate.c b/arch/x86/kvm/emulate.c
index f7970ba6219f..296f8f3ce988 100644
--- a/arch/x86/kvm/emulate.c
+++ b/arch/x86/kvm/emulate.c
@@ -22,7 +22,6 @@
#include "kvm_cache_regs.h"
#include "kvm_emulate.h"
#include <linux/stringify.h>
-#include <asm/fpu/api.h>
#include <asm/debugreg.h>
#include <asm/nospec-branch.h>

@@ -30,6 +29,7 @@
#include "tss.h"
#include "mmu.h"
#include "pmu.h"
+#include "fpu.h"

/*
* Operand types
@@ -1081,116 +1081,14 @@ static void fetch_register_operand(struct operand *op)
}
}

-static void emulator_get_fpu(void)
-{
- fpregs_lock();
-
- fpregs_assert_state_consistent();
- if (test_thread_flag(TIF_NEED_FPU_LOAD))
- switch_fpu_return();
-}
-
-static void emulator_put_fpu(void)
-{
- fpregs_unlock();
-}
-
-static void read_sse_reg(sse128_t *data, int reg)
-{
- emulator_get_fpu();
- switch (reg) {
- case 0: asm("movdqa %%xmm0, %0" : "=m"(*data)); break;
- case 1: asm("movdqa %%xmm1, %0" : "=m"(*data)); break;
- case 2: asm("movdqa %%xmm2, %0" : "=m"(*data)); break;
- case 3: asm("movdqa %%xmm3, %0" : "=m"(*data)); break;
- case 4: asm("movdqa %%xmm4, %0" : "=m"(*data)); break;
- case 5: asm("movdqa %%xmm5, %0" : "=m"(*data)); break;
- case 6: asm("movdqa %%xmm6, %0" : "=m"(*data)); break;
- case 7: asm("movdqa %%xmm7, %0" : "=m"(*data)); break;
-#ifdef CONFIG_X86_64
- case 8: asm("movdqa %%xmm8, %0" : "=m"(*data)); break;
- case 9: asm("movdqa %%xmm9, %0" : "=m"(*data)); break;
- case 10: asm("movdqa %%xmm10, %0" : "=m"(*data)); break;
- case 11: asm("movdqa %%xmm11, %0" : "=m"(*data)); break;
- case 12: asm("movdqa %%xmm12, %0" : "=m"(*data)); break;
- case 13: asm("movdqa %%xmm13, %0" : "=m"(*data)); break;
- case 14: asm("movdqa %%xmm14, %0" : "=m"(*data)); break;
- case 15: asm("movdqa %%xmm15, %0" : "=m"(*data)); break;
-#endif
- default: BUG();
- }
- emulator_put_fpu();
-}
-
-static void write_sse_reg(sse128_t *data, int reg)
-{
- emulator_get_fpu();
- switch (reg) {
- case 0: asm("movdqa %0, %%xmm0" : : "m"(*data)); break;
- case 1: asm("movdqa %0, %%xmm1" : : "m"(*data)); break;
- case 2: asm("movdqa %0, %%xmm2" : : "m"(*data)); break;
- case 3: asm("movdqa %0, %%xmm3" : : "m"(*data)); break;
- case 4: asm("movdqa %0, %%xmm4" : : "m"(*data)); break;
- case 5: asm("movdqa %0, %%xmm5" : : "m"(*data)); break;
- case 6: asm("movdqa %0, %%xmm6" : : "m"(*data)); break;
- case 7: asm("movdqa %0, %%xmm7" : : "m"(*data)); break;
-#ifdef CONFIG_X86_64
- case 8: asm("movdqa %0, %%xmm8" : : "m"(*data)); break;
- case 9: asm("movdqa %0, %%xmm9" : : "m"(*data)); break;
- case 10: asm("movdqa %0, %%xmm10" : : "m"(*data)); break;
- case 11: asm("movdqa %0, %%xmm11" : : "m"(*data)); break;
- case 12: asm("movdqa %0, %%xmm12" : : "m"(*data)); break;
- case 13: asm("movdqa %0, %%xmm13" : : "m"(*data)); break;
- case 14: asm("movdqa %0, %%xmm14" : : "m"(*data)); break;
- case 15: asm("movdqa %0, %%xmm15" : : "m"(*data)); break;
-#endif
- default: BUG();
- }
- emulator_put_fpu();
-}
-
-static void read_mmx_reg(u64 *data, int reg)
-{
- emulator_get_fpu();
- switch (reg) {
- case 0: asm("movq %%mm0, %0" : "=m"(*data)); break;
- case 1: asm("movq %%mm1, %0" : "=m"(*data)); break;
- case 2: asm("movq %%mm2, %0" : "=m"(*data)); break;
- case 3: asm("movq %%mm3, %0" : "=m"(*data)); break;
- case 4: asm("movq %%mm4, %0" : "=m"(*data)); break;
- case 5: asm("movq %%mm5, %0" : "=m"(*data)); break;
- case 6: asm("movq %%mm6, %0" : "=m"(*data)); break;
- case 7: asm("movq %%mm7, %0" : "=m"(*data)); break;
- default: BUG();
- }
- emulator_put_fpu();
-}
-
-static void write_mmx_reg(u64 *data, int reg)
-{
- emulator_get_fpu();
- switch (reg) {
- case 0: asm("movq %0, %%mm0" : : "m"(*data)); break;
- case 1: asm("movq %0, %%mm1" : : "m"(*data)); break;
- case 2: asm("movq %0, %%mm2" : : "m"(*data)); break;
- case 3: asm("movq %0, %%mm3" : : "m"(*data)); break;
- case 4: asm("movq %0, %%mm4" : : "m"(*data)); break;
- case 5: asm("movq %0, %%mm5" : : "m"(*data)); break;
- case 6: asm("movq %0, %%mm6" : : "m"(*data)); break;
- case 7: asm("movq %0, %%mm7" : : "m"(*data)); break;
- default: BUG();
- }
- emulator_put_fpu();
-}
-
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);

- emulator_get_fpu();
+ kvm_fpu_get();
asm volatile("fninit");
- emulator_put_fpu();
+ kvm_fpu_put();
return X86EMUL_CONTINUE;
}

@@ -1201,9 +1099,9 @@ 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);

- emulator_get_fpu();
+ kvm_fpu_get();
asm volatile("fnstcw %0": "+m"(fcw));
- emulator_put_fpu();
+ kvm_fpu_put();

ctxt->dst.val = fcw;

@@ -1217,9 +1115,9 @@ 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);

- emulator_get_fpu();
+ kvm_fpu_get();
asm volatile("fnstsw %0": "+m"(fsw));
- emulator_put_fpu();
+ kvm_fpu_put();

ctxt->dst.val = fsw;

@@ -1238,7 +1136,7 @@ static void decode_register_operand(struct x86_emulate_ctxt *ctxt,
op->type = OP_XMM;
op->bytes = 16;
op->addr.xmm = reg;
- read_sse_reg(&op->vec_val, reg);
+ kvm_read_sse_reg(reg, &op->vec_val);
return;
}
if (ctxt->d & Mmx) {
@@ -1289,7 +1187,7 @@ static int decode_modrm(struct x86_emulate_ctxt *ctxt,
op->type = OP_XMM;
op->bytes = 16;
op->addr.xmm = ctxt->modrm_rm;
- read_sse_reg(&op->vec_val, ctxt->modrm_rm);
+ kvm_read_sse_reg(ctxt->modrm_rm, &op->vec_val);
return rc;
}
if (ctxt->d & Mmx) {
@@ -1866,10 +1764,10 @@ static int writeback(struct x86_emulate_ctxt *ctxt, struct operand *op)
op->bytes * op->count);
break;
case OP_XMM:
- write_sse_reg(&op->vec_val, op->addr.xmm);
+ kvm_write_sse_reg(op->addr.xmm, &op->vec_val);
break;
case OP_MM:
- write_mmx_reg(&op->mm_val, op->addr.mm);
+ kvm_write_mmx_reg(op->addr.mm, &op->mm_val);
break;
case OP_NONE:
/* no writeback */
@@ -4124,11 +4022,11 @@ static int em_fxsave(struct x86_emulate_ctxt *ctxt)
if (rc != X86EMUL_CONTINUE)
return rc;

- emulator_get_fpu();
+ kvm_fpu_get();

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

- emulator_put_fpu();
+ kvm_fpu_put();

if (rc != X86EMUL_CONTINUE)
return rc;
@@ -4172,7 +4070,7 @@ static int em_fxrstor(struct x86_emulate_ctxt *ctxt)
if (rc != X86EMUL_CONTINUE)
return rc;

- emulator_get_fpu();
+ kvm_fpu_get();

if (size < __fxstate_size(16)) {
rc = fxregs_fixup(&fx_state, size);
@@ -4189,7 +4087,7 @@ static int em_fxrstor(struct x86_emulate_ctxt *ctxt)
rc = asm_safe("fxrstor %[fx]", : [fx] "m"(fx_state));

out:
- emulator_put_fpu();
+ kvm_fpu_put();

return rc;
}
@@ -5510,9 +5408,9 @@ static int flush_pending_x87_faults(struct x86_emulate_ctxt *ctxt)
{
int rc;

- emulator_get_fpu();
+ kvm_fpu_get();
rc = asm_safe("fwait");
- emulator_put_fpu();
+ kvm_fpu_put();

if (unlikely(rc != X86EMUL_CONTINUE))
return emulate_exception(ctxt, MF_VECTOR, 0, false);
@@ -5523,7 +5421,7 @@ static int flush_pending_x87_faults(struct x86_emulate_ctxt *ctxt)
static void fetch_possible_mmx_operand(struct operand *op)
{
if (op->type == OP_MM)
- read_mmx_reg(&op->mm_val, op->addr.mm);
+ kvm_read_mmx_reg(op->addr.mm, &op->mm_val);
}

static int fastop(struct x86_emulate_ctxt *ctxt, fastop_t fop)
diff --git a/arch/x86/kvm/fpu.h b/arch/x86/kvm/fpu.h
new file mode 100644
index 000000000000..3ba12888bf66
--- /dev/null
+++ b/arch/x86/kvm/fpu.h
@@ -0,0 +1,140 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+
+#ifndef __KVM_FPU_H_
+#define __KVM_FPU_H_
+
+#include <asm/fpu/api.h>
+
+typedef u32 __attribute__((vector_size(16))) sse128_t;
+#define __sse128_u union { sse128_t vec; u64 as_u64[2]; u32 as_u32[4]; }
+#define sse128_lo(x) ({ __sse128_u t; t.vec = x; t.as_u64[0]; })
+#define sse128_hi(x) ({ __sse128_u t; t.vec = x; t.as_u64[1]; })
+#define sse128_l0(x) ({ __sse128_u t; t.vec = x; t.as_u32[0]; })
+#define sse128_l1(x) ({ __sse128_u t; t.vec = x; t.as_u32[1]; })
+#define sse128_l2(x) ({ __sse128_u t; t.vec = x; t.as_u32[2]; })
+#define sse128_l3(x) ({ __sse128_u t; t.vec = x; t.as_u32[3]; })
+#define sse128(lo, hi) ({ __sse128_u t; t.as_u64[0] = lo; t.as_u64[1] = hi; t.vec; })
+
+static inline void _kvm_read_sse_reg(int reg, sse128_t *data)
+{
+ switch (reg) {
+ case 0: asm("movdqa %%xmm0, %0" : "=m"(*data)); break;
+ case 1: asm("movdqa %%xmm1, %0" : "=m"(*data)); break;
+ case 2: asm("movdqa %%xmm2, %0" : "=m"(*data)); break;
+ case 3: asm("movdqa %%xmm3, %0" : "=m"(*data)); break;
+ case 4: asm("movdqa %%xmm4, %0" : "=m"(*data)); break;
+ case 5: asm("movdqa %%xmm5, %0" : "=m"(*data)); break;
+ case 6: asm("movdqa %%xmm6, %0" : "=m"(*data)); break;
+ case 7: asm("movdqa %%xmm7, %0" : "=m"(*data)); break;
+#ifdef CONFIG_X86_64
+ case 8: asm("movdqa %%xmm8, %0" : "=m"(*data)); break;
+ case 9: asm("movdqa %%xmm9, %0" : "=m"(*data)); break;
+ case 10: asm("movdqa %%xmm10, %0" : "=m"(*data)); break;
+ case 11: asm("movdqa %%xmm11, %0" : "=m"(*data)); break;
+ case 12: asm("movdqa %%xmm12, %0" : "=m"(*data)); break;
+ case 13: asm("movdqa %%xmm13, %0" : "=m"(*data)); break;
+ case 14: asm("movdqa %%xmm14, %0" : "=m"(*data)); break;
+ case 15: asm("movdqa %%xmm15, %0" : "=m"(*data)); break;
+#endif
+ default: BUG();
+ }
+}
+
+static inline void _kvm_write_sse_reg(int reg, const sse128_t *data)
+{
+ switch (reg) {
+ case 0: asm("movdqa %0, %%xmm0" : : "m"(*data)); break;
+ case 1: asm("movdqa %0, %%xmm1" : : "m"(*data)); break;
+ case 2: asm("movdqa %0, %%xmm2" : : "m"(*data)); break;
+ case 3: asm("movdqa %0, %%xmm3" : : "m"(*data)); break;
+ case 4: asm("movdqa %0, %%xmm4" : : "m"(*data)); break;
+ case 5: asm("movdqa %0, %%xmm5" : : "m"(*data)); break;
+ case 6: asm("movdqa %0, %%xmm6" : : "m"(*data)); break;
+ case 7: asm("movdqa %0, %%xmm7" : : "m"(*data)); break;
+#ifdef CONFIG_X86_64
+ case 8: asm("movdqa %0, %%xmm8" : : "m"(*data)); break;
+ case 9: asm("movdqa %0, %%xmm9" : : "m"(*data)); break;
+ case 10: asm("movdqa %0, %%xmm10" : : "m"(*data)); break;
+ case 11: asm("movdqa %0, %%xmm11" : : "m"(*data)); break;
+ case 12: asm("movdqa %0, %%xmm12" : : "m"(*data)); break;
+ case 13: asm("movdqa %0, %%xmm13" : : "m"(*data)); break;
+ case 14: asm("movdqa %0, %%xmm14" : : "m"(*data)); break;
+ case 15: asm("movdqa %0, %%xmm15" : : "m"(*data)); break;
+#endif
+ default: BUG();
+ }
+}
+
+static inline void _kvm_read_mmx_reg(int reg, u64 *data)
+{
+ switch (reg) {
+ case 0: asm("movq %%mm0, %0" : "=m"(*data)); break;
+ case 1: asm("movq %%mm1, %0" : "=m"(*data)); break;
+ case 2: asm("movq %%mm2, %0" : "=m"(*data)); break;
+ case 3: asm("movq %%mm3, %0" : "=m"(*data)); break;
+ case 4: asm("movq %%mm4, %0" : "=m"(*data)); break;
+ case 5: asm("movq %%mm5, %0" : "=m"(*data)); break;
+ case 6: asm("movq %%mm6, %0" : "=m"(*data)); break;
+ case 7: asm("movq %%mm7, %0" : "=m"(*data)); break;
+ default: BUG();
+ }
+}
+
+static inline void _kvm_write_mmx_reg(int reg, const u64 *data)
+{
+ switch (reg) {
+ case 0: asm("movq %0, %%mm0" : : "m"(*data)); break;
+ case 1: asm("movq %0, %%mm1" : : "m"(*data)); break;
+ case 2: asm("movq %0, %%mm2" : : "m"(*data)); break;
+ case 3: asm("movq %0, %%mm3" : : "m"(*data)); break;
+ case 4: asm("movq %0, %%mm4" : : "m"(*data)); break;
+ case 5: asm("movq %0, %%mm5" : : "m"(*data)); break;
+ case 6: asm("movq %0, %%mm6" : : "m"(*data)); break;
+ case 7: asm("movq %0, %%mm7" : : "m"(*data)); break;
+ default: BUG();
+ }
+}
+
+static inline void kvm_fpu_get(void)
+{
+ fpregs_lock();
+
+ fpregs_assert_state_consistent();
+ if (test_thread_flag(TIF_NEED_FPU_LOAD))
+ switch_fpu_return();
+}
+
+static inline void kvm_fpu_put(void)
+{
+ fpregs_unlock();
+}
+
+static inline void kvm_read_sse_reg(int reg, sse128_t *data)
+{
+ kvm_fpu_get();
+ _kvm_read_sse_reg(reg, data);
+ kvm_fpu_put();
+}
+
+static inline void kvm_write_sse_reg(int reg, const sse128_t *data)
+{
+ kvm_fpu_get();
+ _kvm_write_sse_reg(reg, data);
+ kvm_fpu_put();
+}
+
+static inline void kvm_read_mmx_reg(int reg, u64 *data)
+{
+ kvm_fpu_get();
+ _kvm_read_mmx_reg(reg, data);
+ kvm_fpu_put();
+}
+
+static inline void kvm_write_mmx_reg(int reg, const u64 *data)
+{
+ kvm_fpu_get();
+ _kvm_write_mmx_reg(reg, data);
+ kvm_fpu_put();
+}
+
+#endif
--
2.17.1