Avi Kivity wrote:
> Jan Kiszka wrote:
>> This patch reworks the KVM-related layout and encoding of the CPU state
>> to be saved to disk or migrated. The goal is to define a format, version
>> 9, that is also acceptable for upstream and can later be merged into
>> QEMU. Besides unconditionally writing KVM states, this format compresses
>> interrupt_bitmap into a single number as there can be no more than one
>> pending IRQ at a time.
>>
>>
>> - if (kvm_enabled()) {
>> - for (i = 0; i < sizeof(env->interrupt_bitmap)/8 ; i++) {
>> - qemu_put_be64s(f, &env->interrupt_bitmap[i]);
>> + /* KVM-related states */
>> +
>> + /* There can only be one pending IRQ set in the bitmap at a time,
>> so try
>> + to find it and save its number instead (-1 for none). */
>> + pending_irq = -1;
>> + for (i = 0; i < sizeof(env->interrupt_bitmap)/2; i++) {
>> + bit = ffs(((uint16_t *)env->interrupt_bitmap)[i]);
>> + if (bit) {
>> + pending_irq = i * 16 + bit;
>>
>
> bit - 1
Fixed.
>
>> + break;
>> }
>>
>
> Why are you using uint64_t? It would be more natural to use ffsll and
> the natural type of the bitmap vector.
Better don't ask how I interpreted the ffs doc.
>
>> + } else {
>> + kvm_load_registers(env);
>> + kvm_load_tsc(env);
>> kvm_load_mpstate(env);
>> }
>> }
>>
>
> Don't you need to load the pending interrupt?
>
For >= v9 this is done in the previous hunk.
------------>
This patch reworks the KVM-related layout and encoding of the CPU state
to be saved to disk or migrated. The goal is to define a format, version
9, that is also acceptable for upstream and can later be merged into
QEMU. Besides unconditionally writing KVM states, this format compresses
interrupt_bitmap into a single number as there can be no more than one
pending IRQ at a time.
Changes in v2:
- fixed and simplified interrupt_bitmap parsing
Signed-off-by: Jan Kiszka <jan.kiszka@xxxxxxxxxxx>
---
target-i386/cpu.h | 2 +-
target-i386/machine.c | 57 +++++++++++++++++++++++++++++++++++--------------
2 files changed, 42 insertions(+), 17 deletions(-)
diff --git a/target-i386/cpu.h b/target-i386/cpu.h
index f054af1..e07b504 100644
--- a/target-i386/cpu.h
+++ b/target-i386/cpu.h
@@ -838,7 +838,7 @@ static inline int cpu_get_time_fast(void)
#define cpu_signal_handler cpu_x86_signal_handler
#define cpu_list x86_cpu_list
-#define CPU_SAVE_VERSION 8
+#define CPU_SAVE_VERSION 9
/* MMU modes definitions */
#define MMU_MODE0_SUFFIX _kernel
diff --git a/target-i386/machine.c b/target-i386/machine.c
index 59472d0..67a6e60 100644
--- a/target-i386/machine.c
+++ b/target-i386/machine.c
@@ -28,7 +28,8 @@ void cpu_save(QEMUFile *f, void *opaque)
uint16_t fptag, fpus, fpuc, fpregs_format;
uint32_t hflags;
int32_t a20_mask;
- int i;
+ int32_t pending_irq;
+ int i, bit;
if (kvm_enabled()) {
kvm_save_registers(env);
@@ -143,13 +144,21 @@ void cpu_save(QEMUFile *f, void *opaque)
qemu_put_be64s(f, &env->mtrr_var[i].mask);
}
- if (kvm_enabled()) {
- for (i = 0; i < sizeof(env->interrupt_bitmap)/8 ; i++) {
- qemu_put_be64s(f, &env->interrupt_bitmap[i]);
+ /* KVM-related states */
+
+ /* There can only be one pending IRQ set in the bitmap at a time, so try
+ to find it and save its number instead (-1 for none). */
+ pending_irq = -1;
+ for (i = 0; i < ARRAY_SIZE(env->interrupt_bitmap); i++) {
+ bit = ffsll(env->interrupt_bitmap[i]);
+ if (bit) {
+ pending_irq = i * 64 + bit - 1;
+ break;
}
- qemu_put_be64s(f, &env->tsc);
- qemu_put_be32s(f, &env->mp_state);
}
+ qemu_put_sbe32s(f, &pending_irq);
+ qemu_put_be32s(f, &env->mp_state);
+ qemu_put_be64s(f, &env->tsc);
}
#ifdef USE_X86LDOUBLE
@@ -183,9 +192,9 @@ int cpu_load(QEMUFile *f, void *opaque, int version_id)
uint32_t hflags;
uint16_t fpus, fpuc, fptag, fpregs_format;
int32_t a20_mask;
+ int32_t pending_irq;
- if (version_id != 3 && version_id != 4 && version_id != 5
- && version_id != 6 && version_id != 7 && version_id != 8)
+ if (version_id < 3 || version_id > CPU_SAVE_VERSION)
return -EINVAL;
for(i = 0; i < CPU_NB_REGS; i++)
qemu_get_betls(f, &env->regs[i]);
@@ -330,6 +339,16 @@ int cpu_load(QEMUFile *f, void *opaque, int version_id)
}
}
+ if (version_id >= 9) {
+ qemu_get_sbe32s(f, &pending_irq);
+ memset(&env->interrupt_bitmap, 0, sizeof(env->interrupt_bitmap));
+ if (pending_irq >= 0) {
+ env->interrupt_bitmap[pending_irq / 64] |= 1 << (pending_irq % 64);
+ }
+ qemu_get_be32s(f, &env->mp_state);
+ qemu_get_be64s(f, &env->tsc);
+ }
+
/* XXX: ensure compatiblity for halted bit ? */
/* XXX: compute redundant hflags bits */
env->hflags = hflags;
@@ -338,14 +357,20 @@ int cpu_load(QEMUFile *f, void *opaque, int version_id)
/* when in-kernel irqchip is used, env->halted causes deadlock
because no userspace IRQs will ever clear this flag */
env->halted = 0;
- for (i = 0; i < sizeof(env->interrupt_bitmap)/8; i++) {
- qemu_get_be64s(f, &env->interrupt_bitmap[i]);
- }
- qemu_get_be64s(f, &env->tsc);
- kvm_load_registers(env);
- kvm_load_tsc(env);
- if (version_id >= 5) {
- qemu_get_be32s(f, &env->mp_state);
+ if (version_id < 9) {
+ for (i = 0; i < sizeof(env->interrupt_bitmap)/8; i++) {
+ qemu_get_be64s(f, &env->interrupt_bitmap[i]);
+ }
+ qemu_get_be64s(f, &env->tsc);
+ kvm_load_registers(env);
+ kvm_load_tsc(env);
+ if (version_id >= 5) {
+ qemu_get_be32s(f, &env->mp_state);
+ kvm_load_mpstate(env);
+ }
+ } else {
+ kvm_load_registers(env);
+ kvm_load_tsc(env);
kvm_load_mpstate(env);
}
}
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