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[Qemu-devel] Re: [PATCH-RFC 0/3] qemu: memory barriers in virtio
From: |
Michael S. Tsirkin |
Subject: |
[Qemu-devel] Re: [PATCH-RFC 0/3] qemu: memory barriers in virtio |
Date: |
Tue, 22 Dec 2009 13:26:01 +0200 |
User-agent: |
Mutt/1.5.19 (2009-01-05) |
On Tue, Dec 08, 2009 at 06:18:18PM +0200, Michael S. Tsirkin wrote:
> The following fixes a class of long-standing bugs in qemu:
> when kvm is enabled, guest might access device structures
> in memory while they are updated by qemu on another CPU.
> In this scenario, memory barriers are necessary to prevent
> host CPU from reordering memory accesses, which might confuse
> the guest.
>
> This patch only fixes virtio, but other emulated devices
> might have a similar bug. They'll need to be discovered
> and addressed case by case.
>
> This is still under test ... meanwhile: any early feedback/flames?
>
Any comments on this one?
The patch works fine in my testing, and even though
it did not fix a crash that I hoped it will fix,
it seems required for correctness... Right?
> Michael S. Tsirkin (3):
> qemu: add barriers.h header
> virtio: use a real wmb
> virtio: add missing barriers
>
> hw/barriers.h | 131
> +++++++++++++++++++++++++++++++++++++++++++++++++++++++++
> hw/virtio.c | 18 ++++----
> 2 files changed, 139 insertions(+), 10 deletions(-)
> create mode 100644 hw/barriers.h
>
- [Qemu-devel] [PATCH-RFC 0/3] qemu: memory barriers in virtio, Michael S. Tsirkin, 2009/12/08
- [Qemu-devel] Re: [PATCH-RFC 0/3] qemu: memory barriers in virtio,
Michael S. Tsirkin <=
- [Qemu-devel] Re: [PATCH-RFC 0/3] qemu: memory barriers in virtio, Anthony Liguori, 2009/12/22
- [Qemu-devel] Re: [PATCH-RFC 0/3] qemu: memory barriers in virtio, Paul Brook, 2009/12/22
- [Qemu-devel] Re: [PATCH-RFC 0/3] qemu: memory barriers in virtio, Michael S. Tsirkin, 2009/12/22
- [Qemu-devel] Re: [PATCH-RFC 0/3] qemu: memory barriers in virtio, Paul Brook, 2009/12/22
- [Qemu-devel] Re: [PATCH-RFC 0/3] qemu: memory barriers in virtio, Michael S. Tsirkin, 2009/12/23
- [Qemu-devel] Re: [PATCH-RFC 0/3] qemu: memory barriers in virtio, Paul Brook, 2009/12/23
- [Qemu-devel] Re: [PATCH-RFC 0/3] qemu: memory barriers in virtio, Michael S. Tsirkin, 2009/12/23
- [Qemu-devel] Re: [PATCH-RFC 0/3] qemu: memory barriers in virtio, Michael S. Tsirkin, 2009/12/23
- [Qemu-devel] Re: [PATCH-RFC 0/3] qemu: memory barriers in virtio, Paul Brook, 2009/12/23
- [Qemu-devel] Re: [PATCH-RFC 0/3] qemu: memory barriers in virtio, Michael S. Tsirkin, 2009/12/23