From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mailman by lists.gnu.org with tmda-scanned (Exim 4.43) id 1MRoZJ-00062n-4A for qemu-devel@nongnu.org; Fri, 17 Jul 2009 10:37:49 -0400 Received: from exim by lists.gnu.org with spam-scanned (Exim 4.43) id 1MRoZE-0005yK-Cr for qemu-devel@nongnu.org; Fri, 17 Jul 2009 10:37:48 -0400 Received: from [199.232.76.173] (port=58530 helo=monty-python.gnu.org) by lists.gnu.org with esmtp (Exim 4.43) id 1MRoZE-0005yH-7k for qemu-devel@nongnu.org; Fri, 17 Jul 2009 10:37:44 -0400 Received: from lizzard.sbs.de ([194.138.37.39]:22974) by monty-python.gnu.org with esmtps (TLS-1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.60) (envelope-from ) id 1MRoZD-00085C-Ju for qemu-devel@nongnu.org; Fri, 17 Jul 2009 10:37:44 -0400 Message-ID: <4A608CB5.7000802@siemens.com> Date: Fri, 17 Jul 2009 16:37:41 +0200 From: Jan Kiszka MIME-Version: 1.0 References: <1247831508-19023-1-git-send-email-agraf@suse.de> <1247831508-19023-2-git-send-email-agraf@suse.de> <1247831508-19023-3-git-send-email-agraf@suse.de> <1247831508-19023-4-git-send-email-agraf@suse.de> <1247831508-19023-5-git-send-email-agraf@suse.de> <1247831508-19023-6-git-send-email-agraf@suse.de> <1247831508-19023-7-git-send-email-agraf@suse.de> <1247831508-19023-8-git-send-email-agraf@suse.de> In-Reply-To: <1247831508-19023-8-git-send-email-agraf@suse.de> Content-Type: text/plain; charset=ISO-8859-15 Content-Transfer-Encoding: 7bit Subject: [Qemu-devel] Re: [PATCH 7/7] Fake dirty loggin when it's not there List-Id: qemu-devel.nongnu.org List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Alexander Graf Cc: qemu-devel@nongnu.org, hollisb@us.ibm.com 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 > --- > 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