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Re: [Qemu-devel] [PATCHv2 1/3] qemu: memory notifiers
From: |
Michael S. Tsirkin |
Subject: |
Re: [Qemu-devel] [PATCHv2 1/3] qemu: memory notifiers |
Date: |
Mon, 18 Jan 2010 16:44:56 +0200 |
User-agent: |
Mutt/1.5.19 (2009-01-05) |
On Mon, Jan 18, 2010 at 03:58:51PM +0200, Avi Kivity wrote:
> On 01/18/2010 03:52 PM, Michael S. Tsirkin wrote:
>> On Mon, Jan 18, 2010 at 03:02:59PM +0200, Avi Kivity wrote:
>>
>>> On 01/04/2010 09:49 PM, Michael S. Tsirkin wrote:
>>>
>>>> This adds notifiers for phys memory changes: a set of callbacks that
>>>> vhost can register and update kernel accordingly. Down the road, kvm
>>>> code can be switched to use these as well, instead of calling kvm code
>>>> directly from exec.c as is done now.
>>>>
>>>>
>>>> +
>>>> +static void phys_page_for_each_in_l1_map(PhysPageDesc **phys_map,
>>>> + CPUPhysMemoryClient *client)
>>>> +{
>>>> + PhysPageDesc *pd;
>>>> + int l1, l2;
>>>> +
>>>> + for (l1 = 0; l1< L1_SIZE; ++l1) {
>>>> + pd = phys_map[l1];
>>>> + if (!pd) {
>>>> + continue;
>>>> + }
>>>> + for (l2 = 0; l2< L2_SIZE; ++l2) {
>>>> + if (pd[l2].phys_offset == IO_MEM_UNASSIGNED) {
>>>> + continue;
>>>> + }
>>>> + client->set_memory(client, pd[l2].region_offset,
>>>> + TARGET_PAGE_SIZE, pd[l2].phys_offset);
>>>> + }
>>>> + }
>>>> +}
>>>> +
>>>> +static void phys_page_for_each(CPUPhysMemoryClient *client)
>>>> +{
>>>> +#if TARGET_PHYS_ADDR_SPACE_BITS> 32
>>>> +
>>>> +#if TARGET_PHYS_ADDR_SPACE_BITS> (32 + L1_BITS)
>>>> +#error unsupported TARGET_PHYS_ADDR_SPACE_BITS
>>>> +#endif
>>>> + void **phys_map = (void **)l1_phys_map;
>>>> + int l1;
>>>> + if (!l1_phys_map) {
>>>> + return;
>>>> + }
>>>> + for (l1 = 0; l1< L1_SIZE; ++l1) {
>>>> + if (phys_map[l1]) {
>>>> + phys_page_for_each_in_l1_map(phys_map[l1], client);
>>>> + }
>>>> + }
>>>> +#else
>>>> + if (!l1_phys_map) {
>>>> + return;
>>>> + }
>>>> + phys_page_for_each_in_l1_map(l1_phys_map, client);
>>>> +#endif
>>>> +}
>>>>
>>>>
>>> This looks pretty frightening. What is it needed for?
>>>
>> The point is that clients can be registered at any point.
>>
>> A client that registered when memory is present needs to
>> be notified about it.
>>
>
> It looks very expensive.
Shouldn't be hard to optimize ...
> Maybe we mandate clients be registered at init-time?
This might be tricky - vhost currently only registers when the
first device is hot-added.
> Long term we need to move to a range based memory description.
>
> --
> error compiling committee.c: too many arguments to function
- [Qemu-devel] [PATCHv2 1/3] qemu: memory notifiers, Michael S. Tsirkin, 2010/01/05
- Re: [Qemu-devel] [PATCHv2 1/3] qemu: memory notifiers, Avi Kivity, 2010/01/18
- Re: [Qemu-devel] [PATCHv2 1/3] qemu: memory notifiers, Michael S. Tsirkin, 2010/01/18
- Re: [Qemu-devel] [PATCHv2 1/3] qemu: memory notifiers, Avi Kivity, 2010/01/18
- Re: [Qemu-devel] [PATCHv2 1/3] qemu: memory notifiers,
Michael S. Tsirkin <=
- Re: [Qemu-devel] [PATCHv2 1/3] qemu: memory notifiers, Avi Kivity, 2010/01/18
- Re: [Qemu-devel] [PATCHv2 1/3] qemu: memory notifiers, Michael S. Tsirkin, 2010/01/18
- Re: [Qemu-devel] [PATCHv2 1/3] qemu: memory notifiers, Michael S. Tsirkin, 2010/01/18
- Re: [Qemu-devel] [PATCHv2 1/3] qemu: memory notifiers, Avi Kivity, 2010/01/18
- Re: [Qemu-devel] [PATCHv2 1/3] qemu: memory notifiers, Michael S. Tsirkin, 2010/01/18
- Re: [Qemu-devel] [PATCHv2 1/3] qemu: memory notifiers, Avi Kivity, 2010/01/18