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[Qemu-devel] Re: [PATCH 7/7] Fake dirty loggin when it's not there
From: |
Jan Kiszka |
Subject: |
[Qemu-devel] Re: [PATCH 7/7] Fake dirty loggin when it's not there |
Date: |
Fri, 17 Jul 2009 16:37:41 +0200 |
User-agent: |
Mozilla/5.0 (X11; U; Linux i686 (x86_64); de; rv:1.8.1.12) Gecko/20080226 SUSE/2.0.0.12-1.1 Thunderbird/2.0.0.12 Mnenhy/0.7.5.666 |
Alexander Graf wrote:
> Some KVM platforms don't support dirty logging yet, like IA64 and PPC,
> so in order to still have screen updates on those, we need to fake it.
>
> This patch just tells the getter function for dirty bitmaps, that all
> pages within a slot are dirty when the slot has dirty logging enabled.
>
> That way we can implement dirty logging on those platforms sometime when
> it drags down performance, but share the rest of the code with dirty
> logging capable platforms.
>
> Signed-off-by: Alexander Graf <address@hidden>
> ---
> kvm-all.c | 13 ++++++++++++-
> 1 files changed, 12 insertions(+), 1 deletions(-)
>
> diff --git a/kvm-all.c b/kvm-all.c
> index 60b76cf..72b7935 100644
> --- a/kvm-all.c
> +++ b/kvm-all.c
> @@ -300,6 +300,7 @@ int kvm_physical_sync_dirty_bitmap(target_phys_addr_t
> start_addr,
> KVMDirtyLog d;
> KVMSlot *mem;
> int ret = 0;
> + int r;
>
> d.dirty_bitmap = NULL;
> while (start_addr < end_addr) {
> @@ -308,6 +309,11 @@ int kvm_physical_sync_dirty_bitmap(target_phys_addr_t
> start_addr,
> break;
> }
>
> + /* We didn't activate dirty logging? Don't care then. */
> + if(!(mem->flags & KVM_MEM_LOG_DIRTY_PAGES)) {
> + continue;
> + }
> +
Isn't this worth a separate patch? Do we already run into this patch on
dirty-logging archs (ie. x86)? I'm still wondering why it's needed.
> size = ((mem->memory_size >> TARGET_PAGE_BITS) + 7) / 8;
> if (!d.dirty_bitmap) {
> d.dirty_bitmap = qemu_malloc(size);
> @@ -319,7 +325,8 @@ int kvm_physical_sync_dirty_bitmap(target_phys_addr_t
> start_addr,
>
> d.slot = mem->slot;
>
> - if (kvm_vm_ioctl(s, KVM_GET_DIRTY_LOG, &d) == -1) {
> + r = kvm_vm_ioctl(s, KVM_GET_DIRTY_LOG, &d);
> + if (r == -EINVAL) {
I would say, better exclude 0 and the error you for missing support here
than to assume only EINVAL is a "real" error.
> dprintf("ioctl failed %d\n", errno);
> ret = -1;
> break;
> @@ -335,6 +342,10 @@ int kvm_physical_sync_dirty_bitmap(target_phys_addr_t
> start_addr,
>
> if ((bitmap[word] >> bit) & 1) {
> cpu_physical_memory_set_dirty(addr);
> + } else if (r < 0) {
> + /* When our KVM implementation doesn't know about dirty
> logging
> + * we can just assume it's always dirty and be fine. */
> + cpu_physical_memory_set_dirty(addr);
> }
> }
> start_addr = phys_addr;
Jan
--
Siemens AG, Corporate Technology, CT SE 2
Corporate Competence Center Embedded Linux
- [Qemu-devel] [PATCH 5/7] Use correct input constant, (continued)
- [Qemu-devel] [PATCH 5/7] Use correct input constant, Alexander Graf, 2009/07/17
- [Qemu-devel] [PATCH 6/7] Set slots more carefully, Alexander Graf, 2009/07/17
- [Qemu-devel] [PATCH 7/7] Fake dirty loggin when it's not there, Alexander Graf, 2009/07/17
- Re: [Qemu-devel] [PATCH 7/7] Fake dirty loggin when it's not there, Stefano Stabellini, 2009/07/17
- Re: [Qemu-devel] [PATCH 7/7] Fake dirty loggin when it's not there, Alexander Graf, 2009/07/17
- Re: [Qemu-devel] [PATCH 7/7] Fake dirty loggin when it's not there, Alexander Graf, 2009/07/17
- Re: [Qemu-devel] [PATCH 7/7] Fake dirty loggin when it's not there, Stefano Stabellini, 2009/07/17
- Re: [Qemu-devel] [PATCH 7/7] Fake dirty loggin when it's not there, Alexander Graf, 2009/07/17
- Re: [Qemu-devel] [PATCH 7/7] Fake dirty loggin when it's not there, Stefano Stabellini, 2009/07/17
- Re: [Qemu-devel] [PATCH 7/7] Fake dirty loggin when it's not there, Alexander Graf, 2009/07/17
- [Qemu-devel] Re: [PATCH 7/7] Fake dirty loggin when it's not there,
Jan Kiszka <=
- [Qemu-devel] Re: [PATCH 7/7] Fake dirty loggin when it's not there, Alexander Graf, 2009/07/17
- [Qemu-devel] Re: [PATCH 7/7] Fake dirty loggin when it's not there, Jan Kiszka, 2009/07/17
- [Qemu-devel] Re: [PATCH 6/7] Set slots more carefully, Jan Kiszka, 2009/07/17
- [Qemu-devel] Re: [PATCH 6/7] Set slots more carefully, Alexander Graf, 2009/07/17
- [Qemu-devel] Re: [PATCH 6/7] Set slots more carefully, Jan Kiszka, 2009/07/17
- [Qemu-devel] Re: [PATCH 6/7] Set slots more carefully, Alexander Graf, 2009/07/17
- [Qemu-devel] Re: [PATCH 6/7] Set slots more carefully, Jan Kiszka, 2009/07/17
- Re: [Qemu-devel] [PATCH 6/7] Set slots more carefully, Anthony Liguori, 2009/07/21
- Re: [Qemu-devel] [PATCH 3/7] Add mp_state to PPC CPU struct, Anthony Liguori, 2009/07/22
- Re: [Qemu-devel] [PATCH 3/7] Add mp_state to PPC CPU struct, Hollis Blanchard, 2009/07/22