summaryrefslogtreecommitdiff
path: root/arch/x86/kvm/emulate.c
diff options
context:
space:
mode:
Diffstat (limited to 'arch/x86/kvm/emulate.c')
-rw-r--r--arch/x86/kvm/emulate.c102
1 files changed, 62 insertions, 40 deletions
diff --git a/arch/x86/kvm/emulate.c b/arch/x86/kvm/emulate.c
index 8079d141792a..290ecf711aec 100644
--- a/arch/x86/kvm/emulate.c
+++ b/arch/x86/kvm/emulate.c
@@ -25,6 +25,7 @@
#include <asm/kvm_emulate.h>
#include <linux/stringify.h>
#include <asm/debugreg.h>
+#include <asm/nospec-branch.h>
#include "x86.h"
#include "tss.h"
@@ -1021,8 +1022,8 @@ static __always_inline u8 test_cc(unsigned int condition, unsigned long flags)
void (*fop)(void) = (void *)em_setcc + 4 * (condition & 0xf);
flags = (flags & EFLAGS_MASK) | X86_EFLAGS_IF;
- asm("push %[flags]; popf; call *%[fastop]"
- : "=a"(rc) : [fastop]"r"(fop), [flags]"r"(flags));
+ asm("push %[flags]; popf; " CALL_NOSPEC
+ : "=a"(rc) : [thunk_target]"r"(fop), [flags]"r"(flags));
return rc;
}
@@ -1046,7 +1047,6 @@ 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;
@@ -1068,13 +1068,11 @@ 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;
@@ -1096,12 +1094,10 @@ 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;
@@ -1113,12 +1109,10 @@ 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;
@@ -1130,7 +1124,6 @@ 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)
@@ -1138,9 +1131,7 @@ 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;
}
@@ -1151,9 +1142,7 @@ 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;
@@ -1167,9 +1156,7 @@ 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;
@@ -2404,9 +2391,21 @@ static int rsm_load_seg_64(struct x86_emulate_ctxt *ctxt, u64 smbase, int n)
}
static int rsm_enter_protected_mode(struct x86_emulate_ctxt *ctxt,
- u64 cr0, u64 cr4)
+ u64 cr0, u64 cr3, u64 cr4)
{
int bad;
+ u64 pcid;
+
+ /* In order to later set CR4.PCIDE, CR3[11:0] must be zero. */
+ pcid = 0;
+ if (cr4 & X86_CR4_PCIDE) {
+ pcid = cr3 & 0xfff;
+ cr3 &= ~0xfff;
+ }
+
+ bad = ctxt->ops->set_cr(ctxt, 3, cr3);
+ if (bad)
+ return X86EMUL_UNHANDLEABLE;
/*
* First enable PAE, long mode needs it before CR0.PG = 1 is set.
@@ -2425,6 +2424,12 @@ static int rsm_enter_protected_mode(struct x86_emulate_ctxt *ctxt,
bad = ctxt->ops->set_cr(ctxt, 4, cr4);
if (bad)
return X86EMUL_UNHANDLEABLE;
+ if (pcid) {
+ bad = ctxt->ops->set_cr(ctxt, 3, cr3 | pcid);
+ if (bad)
+ return X86EMUL_UNHANDLEABLE;
+ }
+
}
return X86EMUL_CONTINUE;
@@ -2435,11 +2440,11 @@ static int rsm_load_state_32(struct x86_emulate_ctxt *ctxt, u64 smbase)
struct desc_struct desc;
struct desc_ptr dt;
u16 selector;
- u32 val, cr0, cr4;
+ u32 val, cr0, cr3, cr4;
int i;
cr0 = GET_SMSTATE(u32, smbase, 0x7ffc);
- ctxt->ops->set_cr(ctxt, 3, GET_SMSTATE(u32, smbase, 0x7ff8));
+ cr3 = GET_SMSTATE(u32, smbase, 0x7ff8);
ctxt->eflags = GET_SMSTATE(u32, smbase, 0x7ff4) | X86_EFLAGS_FIXED;
ctxt->_eip = GET_SMSTATE(u32, smbase, 0x7ff0);
@@ -2481,14 +2486,14 @@ static int rsm_load_state_32(struct x86_emulate_ctxt *ctxt, u64 smbase)
ctxt->ops->set_smbase(ctxt, GET_SMSTATE(u32, smbase, 0x7ef8));
- return rsm_enter_protected_mode(ctxt, cr0, cr4);
+ return rsm_enter_protected_mode(ctxt, cr0, cr3, cr4);
}
static int rsm_load_state_64(struct x86_emulate_ctxt *ctxt, u64 smbase)
{
struct desc_struct desc;
struct desc_ptr dt;
- u64 val, cr0, cr4;
+ u64 val, cr0, cr3, cr4;
u32 base3;
u16 selector;
int i, r;
@@ -2505,7 +2510,7 @@ static int rsm_load_state_64(struct x86_emulate_ctxt *ctxt, u64 smbase)
ctxt->ops->set_dr(ctxt, 7, (val & DR7_VOLATILE) | DR7_FIXED_1);
cr0 = GET_SMSTATE(u64, smbase, 0x7f58);
- ctxt->ops->set_cr(ctxt, 3, GET_SMSTATE(u64, smbase, 0x7f50));
+ cr3 = GET_SMSTATE(u64, smbase, 0x7f50);
cr4 = GET_SMSTATE(u64, smbase, 0x7f48);
ctxt->ops->set_smbase(ctxt, GET_SMSTATE(u32, smbase, 0x7f00));
val = GET_SMSTATE(u64, smbase, 0x7ed0);
@@ -2533,7 +2538,7 @@ static int rsm_load_state_64(struct x86_emulate_ctxt *ctxt, u64 smbase)
dt.address = GET_SMSTATE(u64, smbase, 0x7e68);
ctxt->ops->set_gdt(ctxt, &dt);
- r = rsm_enter_protected_mode(ctxt, cr0, cr4);
+ r = rsm_enter_protected_mode(ctxt, cr0, cr3, cr4);
if (r != X86EMUL_CONTINUE)
return r;
@@ -4001,12 +4006,8 @@ 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;
@@ -4014,6 +4015,26 @@ static int em_fxsave(struct x86_emulate_ctxt *ctxt)
fxstate_size(ctxt));
}
+/*
+ * FXRSTOR might restore XMM registers not provided by the guest. Fill
+ * in the host registers (via FXSAVE) instead, so they won't be modified.
+ * (preemption has to stay disabled until FXRSTOR).
+ *
+ * Use noinline to keep the stack for other functions called by callers small.
+ */
+static noinline int fxregs_fixup(struct fxregs_state *fx_state,
+ const size_t used_size)
+{
+ struct fxregs_state fx_tmp;
+ int rc;
+
+ rc = asm_safe("fxsave %[fx]", , [fx] "+m"(fx_tmp));
+ memcpy((void *)fx_state + used_size, (void *)&fx_tmp + used_size,
+ __fxstate_size(16) - used_size);
+
+ return rc;
+}
+
static int em_fxrstor(struct x86_emulate_ctxt *ctxt)
{
struct fxregs_state fx_state;
@@ -4024,19 +4045,17 @@ static int em_fxrstor(struct x86_emulate_ctxt *ctxt)
if (rc != X86EMUL_CONTINUE)
return rc;
- ctxt->ops->get_fpu(ctxt);
-
size = fxstate_size(ctxt);
+ rc = segmented_read_std(ctxt, ctxt->memop.addr.mem, &fx_state, size);
+ if (rc != X86EMUL_CONTINUE)
+ return rc;
+
if (size < __fxstate_size(16)) {
- rc = asm_safe("fxsave %[fx]", , [fx] "+m"(fx_state));
+ rc = fxregs_fixup(&fx_state, size);
if (rc != X86EMUL_CONTINUE)
goto out;
}
- rc = segmented_read_std(ctxt, ctxt->memop.addr.mem, &fx_state, size);
- if (rc != X86EMUL_CONTINUE)
- goto out;
-
if (fx_state.mxcsr >> 16) {
rc = emulate_gp(ctxt, 0);
goto out;
@@ -4046,8 +4065,6 @@ 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;
}
@@ -5000,6 +5017,8 @@ int x86_decode_insn(struct x86_emulate_ctxt *ctxt, void *insn, int insn_len)
bool op_prefix = false;
bool has_seg_override = false;
struct opcode opcode;
+ u16 dummy;
+ struct desc_struct desc;
ctxt->memop.type = OP_NONE;
ctxt->memopp = NULL;
@@ -5018,6 +5037,11 @@ int x86_decode_insn(struct x86_emulate_ctxt *ctxt, void *insn, int insn_len)
switch (mode) {
case X86EMUL_MODE_REAL:
case X86EMUL_MODE_VM86:
+ def_op_bytes = def_ad_bytes = 2;
+ ctxt->ops->get_segment(ctxt, &dummy, &desc, NULL, VCPU_SREG_CS);
+ if (desc.d)
+ def_op_bytes = def_ad_bytes = 4;
+ break;
case X86EMUL_MODE_PROT16:
def_op_bytes = def_ad_bytes = 2;
break;
@@ -5290,9 +5314,7 @@ 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);
@@ -5314,9 +5336,9 @@ static int fastop(struct x86_emulate_ctxt *ctxt, void (*fop)(struct fastop *))
if (!(ctxt->d & ByteOp))
fop += __ffs(ctxt->dst.bytes) * FASTOP_SIZE;
- asm("push %[flags]; popf; call *%[fastop]; pushf; pop %[flags]\n"
+ asm("push %[flags]; popf; " CALL_NOSPEC " ; pushf; pop %[flags]\n"
: "+a"(ctxt->dst.val), "+d"(ctxt->src.val), [flags]"+D"(flags),
- [fastop]"+S"(fop), ASM_CALL_CONSTRAINT
+ [thunk_target]"+S"(fop), ASM_CALL_CONSTRAINT
: "c"(ctxt->src2.val));
ctxt->eflags = (ctxt->eflags & ~EFLAGS_MASK) | (flags & EFLAGS_MASK);
generated by cgit v1.2.3 (git 2.39.0) at 2024-12-24 01:14:25 +0300