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[Qemu-devel] [PATCH] kvm: Fix error detection for KVM_GET_DIRTY_LOG
From: |
Jan Kiszka |
Subject: |
[Qemu-devel] [PATCH] kvm: Fix error detection for KVM_GET_DIRTY_LOG |
Date: |
Wed, 22 Jul 2009 21:27:53 +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 |
Anthony Liguori wrote:
> Jan Kiszka wrote:
>>> Signed-off-by: Alexander Graf <address@hidden>
>>> Signed-off-by: Anthony Liguori
>>> <aliguori-r/address@hidden>
>>>
>>> diff --git a/kvm-all.c b/kvm-all.c
>>> index 961fa32..2032949 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;
>>> + }
>>> +
>>>
>>
>> According to Alex' reply [1], I think this is probably better expressed
>> as an assert() than a silent skip. It indicates an error at higher
>> level, no?
>>
>
> I don't have a strong opinion either way.
>
>>> 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) {
>>> dprintf("ioctl failed %d\n", errno);
>>> ret = -1;
>>> break;
>>>
>>
>> My remark still stands: This is an "optimistic" assumption that only
>> EINVAL is a "real" error. If KVM is buggy /wrt a specific invalid return
>> value, work around that particular bug (and we should also fix the
>> kernel, but that's a different topic).
>>
>
> The behavior is identical to what it was before. It's just a stylistic
> change.
Not really (EINVAL != 1). But, yes, it's incorrect in similar way. :)
Jan
----------->
Signed-off-by: Jan Kiszka <address@hidden>
---
kvm-all.c | 4 +++-
1 files changed, 3 insertions(+), 1 deletions(-)
diff --git a/kvm-all.c b/kvm-all.c
index 824bb4c..53925be 100644
--- a/kvm-all.c
+++ b/kvm-all.c
@@ -348,7 +348,9 @@ int kvm_physical_sync_dirty_bitmap(target_phys_addr_t
start_addr,
d.slot = mem->slot;
r = kvm_vm_ioctl(s, KVM_GET_DIRTY_LOG, &d);
- if (r == -EINVAL) {
+ /* KVM for PowerPC returns illicit -ENOTSUPP (-524) which we handle
+ * below. */
+ if (r < 0 && r != -524) {
dprintf("ioctl failed %d\n", errno);
ret = -1;
break;
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Description: OpenPGP digital signature
- [Qemu-devel] Re: [COMMIT bd83677] Fake dirty loggin when it's not there, Jan Kiszka, 2009/07/22
- Re: [Qemu-devel] Re: [COMMIT bd83677] Fake dirty loggin when it's not there, Anthony Liguori, 2009/07/22
- [Qemu-devel] [PATCH] kvm: Fix error detection for KVM_GET_DIRTY_LOG,
Jan Kiszka <=
- [Qemu-devel] Re: [PATCH] kvm: Fix error detection for KVM_GET_DIRTY_LOG, Anthony Liguori, 2009/07/22
- [Qemu-devel] Re: [PATCH] kvm: Fix error detection for KVM_GET_DIRTY_LOG, Jan Kiszka, 2009/07/22
- [Qemu-devel] Re: [PATCH] kvm: Fix error detection for KVM_GET_DIRTY_LOG, Anthony Liguori, 2009/07/22
- [Qemu-devel] Re: [PATCH] kvm: Fix error detection for KVM_GET_DIRTY_LOG, Jan Kiszka, 2009/07/22
- [Qemu-devel] Re: [PATCH] kvm: Fix error detection for KVM_GET_DIRTY_LOG, Alexander Graf, 2009/07/22
- [Qemu-devel] Re: [PATCH] kvm: Fix error detection for KVM_GET_DIRTY_LOG, Jan Kiszka, 2009/07/22
- [Qemu-devel] Re: [PATCH] kvm: Fix error detection for KVM_GET_DIRTY_LOG, Alexander Graf, 2009/07/22
- [Qemu-devel] Re: [PATCH] kvm: Fix error detection for KVM_GET_DIRTY_LOG, Anthony Liguori, 2009/07/22
- [Qemu-devel] Re: [PATCH] kvm: Fix error detection for KVM_GET_DIRTY_LOG, Alexander Graf, 2009/07/22
- [Qemu-devel] Re: [PATCH] kvm: Fix error detection for KVM_GET_DIRTY_LOG, Jan Kiszka, 2009/07/22