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[Qemu-devel] Re: [PATCH] remove smaller slots if registering a bigger on
From: |
Jan Kiszka |
Subject: |
[Qemu-devel] Re: [PATCH] remove smaller slots if registering a bigger one |
Date: |
Wed, 11 Feb 2009 15:52:40 +0100 |
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 |
Jan Kiszka wrote:
> Glauber Costa wrote:
>> On Wed, Feb 11, 2009 at 03:23:07PM +0100, Jan Kiszka wrote:
>>> Glauber Costa wrote:
>>>> It's like a shark eating a bunch of small fishes:
>>>> in some situations (vga linear frame buffer mapping,
>>>> for example), we need to register a new slot in place
>>>> of older, smaller ones. This patch handles this case
>>>>
>>>> Signed-off-by: Glauber Costa <address@hidden>
>>>> ---
>>>> kvm-all.c | 10 ++++++++++
>>>> 1 files changed, 10 insertions(+), 0 deletions(-)
>>>>
>>>> diff --git a/kvm-all.c b/kvm-all.c
>>>> index 9fb295c..53aca0a 100644
>>>> --- a/kvm-all.c
>>>> +++ b/kvm-all.c
>>>> @@ -582,6 +582,16 @@ void kvm_set_phys_mem(target_phys_addr_t start_addr,
>>>> kvm_set_phys_mem(mem_start, mem_size, mem_offset);
>>>>
>>>> return;
>>>> + } else if (start_addr <= mem->start_addr &&
>>>> + (start_addr + size) >= (mem->start_addr +
>>>> + mem->memory_size)) {
>>>> + KVMSlot slot;
>>>> + /* unregister whole slot */
>>>> + memcpy(&slot, mem, sizeof(slot));
>>>> + mem->memory_size = 0;
>>>> + kvm_set_user_memory_region(s, mem);
>>>> +
>>>> + kvm_set_phys_mem(start_addr, size, phys_offset);
>>> That may solve some problems, but...
>>>
>>>> } else {
>>>> printf("Registering overlapping slot\n");
>>>> abort();
>>> ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
>>> ...as long as this line exists, issues will remain. IIRC, the mapping
>>> the i440 tries to re-establish after reboot will hit this case.
>> Which is fine. I'd prefer it to be here, so we can analyse it case by case.
>> The old memory code for kvm was totally messy, in part because we tried to
>> hug the world at once, with some code paths that were almost never hit.
>>
>> Slot management can easily get very complicated. and trying to come up
>> with a solution that accounts for all problems at once may backfire on us.
>>
>
> Well, then "fix" all users...
BTW, if you want to play with some problematic case, apply this and
reboot a guest while using -enable-kvm:
diff --git a/vl.c b/vl.c
index ce80690..d53611e 100644
--- a/vl.c
+++ b/vl.c
@@ -3557,6 +3557,8 @@ void qemu_system_reset(void)
for(re = first_reset_entry; re != NULL; re = re->next) {
re->func(re->opaque);
}
+ if (kvm_enabled())
+ kvm_sync_vcpus();
}
void qemu_system_reset_request(void)
Jan
--
Siemens AG, Corporate Technology, CT SE 2
Corporate Competence Center Embedded Linux
- [Qemu-devel] [PATCH] remove smaller slots if registering a bigger one, Glauber Costa, 2009/02/11
- [Qemu-devel] Re: [PATCH] remove smaller slots if registering a bigger one, Jan Kiszka, 2009/02/11
- [Qemu-devel] Re: [PATCH] remove smaller slots if registering a bigger one, Glauber Costa, 2009/02/11
- [Qemu-devel] Re: [PATCH] remove smaller slots if registering a bigger one, Jan Kiszka, 2009/02/11
- [Qemu-devel] Re: [PATCH] remove smaller slots if registering a bigger one,
Jan Kiszka <=
- [Qemu-devel] Re: [PATCH] remove smaller slots if registering a bigger one, Glauber Costa, 2009/02/11
- Re: [Qemu-devel] Re: [PATCH] remove smaller slots if registering a bigger one, Avi Kivity, 2009/02/11
- [Qemu-devel] Re: [PATCH] remove smaller slots if registering a bigger one, Jan Kiszka, 2009/02/11
- Re: [Qemu-devel] Re: [PATCH] remove smaller slots if registering a bigger one, Avi Kivity, 2009/02/11
Re: [Qemu-devel] Re: [PATCH] remove smaller slots if registering a bigger one, Avi Kivity, 2009/02/11