[PATCH][uq/master] kvm: x86: Save/restore FPU OP, IP and DP

Jan Kiszka
2011-06-11T09:23:33Z

From: Jan Kiszka <jan.kiszka@siemens.com>

These FPU states are properly maintained by KVM but not yet by TCG. So
far we unconditionally set them to 0 in the guest which may cause
state corruptions - not only during migration.

Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>
---
target-i386/cpu.h | 6 +++++-
target-i386/kvm.c | 20 +++++++++++++++-----
target-i386/machine.c | 4 ++++
3 files changed, 24 insertions(+), 6 deletions(-)

diff --git a/target-i386/cpu.h b/target-i386/cpu.h
index 9c3340d..3c2dab9 100644
--- a/target-i386/cpu.h
+++ b/target-i386/cpu.h
@@ -641,6 +641,10 @@ typedef struct CPUX86State {
uint16_t fpuc;
uint8_t fptags[8]; /* 0 = valid, 1 = empty */
FPReg fpregs[8];
+ /* KVM-only so far */
+ uint16_t fpop;
+ uint64_t fpip;
+ uint64_t fpdp;

/* emulator internal variables */
float_status fp_status;
@@ -942,7 +946,7 @@ uint64_t cpu_get_tsc(CPUX86State *env);
#define cpu_list_id x86_cpu_list
#define cpudef_setup x86_cpudef_setup

-#define CPU_SAVE_VERSION 12
+#define CPU_SAVE_VERSION 13

/* MMU modes definitions */
#define MMU_MODE0_SUFFIX _kernel
diff --git a/target-i386/kvm.c b/target-i386/kvm.c
index 5ebb054..938e0a3 100644
--- a/target-i386/kvm.c
+++ b/target-i386/kvm.c
@@ -718,6 +718,9 @@ static int kvm_put_fpu(CPUState *env)
fpu.fsw = env->fpus & ~(7 << 11);
fpu.fsw |= (env->fpstt & 7) << 11;
fpu.fcw = env->fpuc;
+ fpu.last_opcode = env->fpop;
+ fpu.last_ip = env->fpip;
+ fpu.last_dp = env->fpdp;
for (i = 0; i < 8; ++i) {
fpu.ftwx |= (!env->fptags[i]) << i;
}
@@ -740,7 +743,7 @@ static int kvm_put_xsave(CPUState *env)
{
int i, r;
struct kvm_xsave* xsave;
- uint16_t cwd, swd, twd, fop;
+ uint16_t cwd, swd, twd;

if (!kvm_has_xsave()) {
return kvm_put_fpu(env);
@@ -748,7 +751,7 @@ static int kvm_put_xsave(CPUState *env)

xsave = qemu_memalign(4096, sizeof(struct kvm_xsave));
memset(xsave, 0, sizeof(struct kvm_xsave));
- cwd = swd = twd = fop = 0;
+ cwd = swd = twd = 0;
swd = env->fpus & ~(7 << 11);
swd |= (env->fpstt & 7) << 11;
cwd = env->fpuc;
@@ -756,7 +759,9 @@ static int kvm_put_xsave(CPUState *env)
twd |= (!env->fptags[i]) << i;
}
xsave->region[0] = (uint32_t)(swd << 16) + cwd;
- xsave->region[1] = (uint32_t)(fop << 16) + twd;
+ xsave->region[1] = (uint32_t)(env->fpop << 16) + twd;
+ memcpy(&xsave->region[XSAVE_CWD_RIP], &env->fpip, sizeof(env->fpip));
+ memcpy(&xsave->region[XSAVE_CWD_RDP], &env->fpdp, sizeof(env->fpdp));
memcpy(&xsave->region[XSAVE_ST_SPACE], env->fpregs,
sizeof env->fpregs);
memcpy(&xsave->region[XSAVE_XMM_SPACE], env->xmm_regs,
@@ -921,6 +926,9 @@ static int kvm_get_fpu(CPUState *env)
env->fpstt = (fpu.fsw >> 11) & 7;
env->fpus = fpu.fsw;
env->fpuc = fpu.fcw;
+ env->fpop = fpu.last_opcode;
+ env->fpip = fpu.last_ip;
+ env->fpdp = fpu.last_dp;
for (i = 0; i < 8; ++i) {
env->fptags[i] = !((fpu.ftwx >> i) & 1);
}
@@ -935,7 +943,7 @@ static int kvm_get_xsave(CPUState *env)
{
struct kvm_xsave* xsave;
int ret, i;
- uint16_t cwd, swd, twd, fop;
+ uint16_t cwd, swd, twd;

if (!kvm_has_xsave()) {
return kvm_get_fpu(env);
@@ -951,13 +959,15 @@ static int kvm_get_xsave(CPUState *env)
cwd = (uint16_t)xsave->region[0];
swd = (uint16_t)(xsave->region[0] >> 16);
twd = (uint16_t)xsave->region[1];
- fop = (uint16_t)(xsave->region[1] >> 16);
+ env->fpop = (uint16_t)(xsave->region[1] >> 16);
env->fpstt = (swd >> 11) & 7;
env->fpus = swd;
env->fpuc = cwd;
for (i = 0; i < 8; ++i) {
env->fptags[i] = !((twd >> i) & 1);
}
+ memcpy(&env->fpip, &xsave->region[XSAVE_CWD_RIP], sizeof(env->fpip));
+ memcpy(&env->fpdp, &xsave->region[XSAVE_CWD_RDP], sizeof(env->fpdp));
env->mxcsr = xsave->region[XSAVE_MXCSR];
memcpy(env->fpregs, &xsave->region[XSAVE_ST_SPACE],
sizeof env->fpregs);
diff --git a/target-i386/machine.c b/target-i386/machine.c
index bbeae88..e02c2a3 100644
--- a/target-i386/machine.c
+++ b/target-i386/machine.c
@@ -390,6 +390,10 @@ static const VMStateDescription vmstate_cpu = {
VMSTATE_UINT64_V(xcr0, CPUState, 12),
VMSTATE_UINT64_V(xstate_bv, CPUState, 12),
VMSTATE_YMMH_REGS_VARS(ymmh_regs, CPUState, CPU_NB_REGS, 12),
+ /* Further FPU states */
+ VMSTATE_UINT16_V(fpop, CPUState, 13),
+ VMSTATE_UINT64_V(fpip, CPUState, 13),
+ VMSTATE_UINT64_V(fpdp, CPUState, 13),
VMSTATE_END_OF_LIST()
/* The above list is not sorted /wrt version numbers, watch out! */
},
--
1.7.1