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[Qemu-devel] Re: [PATCH] KVM: x86: Refactor persistent CPU state
From: |
Anthony Liguori |
Subject: |
[Qemu-devel] Re: [PATCH] KVM: x86: Refactor persistent CPU state |
Date: |
Thu, 28 May 2009 02:33:59 -0500 |
User-agent: |
Thunderbird 2.0.0.21 (X11/20090409) |
Jan Kiszka wrote:
> This patch aligns the KVM-related layout and encoding of the CPU state
> to be saved to disk or migrated with qemu-kvm. The major differences are
> reordering of fields and a compressed interrupt_bitmap into a single
> number as there can be no more than one pending IRQ at a time.
>
> Signed-off-by: Jan Kiszka <address@hidden>
>
We need a version bump, no?
Regards,
Anthony Liguori
> ---
>
> target-i386/machine.c | 30 +++++++++++++++++++++++-------
> 1 files changed, 23 insertions(+), 7 deletions(-)
>
> diff --git a/target-i386/machine.c b/target-i386/machine.c
> index bb8b9db..259302c 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;
>
> cpu_synchronize_state(env, 0);
>
> @@ -141,11 +142,21 @@ void cpu_save(QEMUFile *f, void *opaque)
> qemu_put_be64s(f, &env->mtrr_var[i].mask);
> }
>
> - 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_sbe32s(f, &pending_irq);
> qemu_put_be32s(f, &env->mp_state);
> + qemu_put_be64s(f, &env->tsc);
> }
>
> #ifdef USE_X86LDOUBLE
> @@ -179,6 +190,7 @@ 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 > CPU_SAVE_VERSION)
> return -EINVAL;
> @@ -324,12 +336,16 @@ int cpu_load(QEMUFile *f, void *opaque, int version_id)
> qemu_get_be64s(f, &env->mtrr_var[i].mask);
> }
> }
> +
> if (version_id >= 9) {
> - for (i = 0; i < sizeof(env->interrupt_bitmap)/8; i++) {
> - qemu_get_be64s(f, &env->interrupt_bitmap[i]);
> + 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] |=
> + (uint64_t)1 << (pending_irq % 64);
> }
> - qemu_get_be64s(f, &env->tsc);
> qemu_get_be32s(f, &env->mp_state);
> + qemu_get_be64s(f, &env->tsc);
> }
>
> /* XXX: ensure compatiblity for halted bit ? */
>
>