Re: [PULL 00/51] Net patches

[Michael S. Tsirkin]

On Wed, Mar 08, 2023 at 01:21:52PM +0100, Philippe Mathieu-Daudé wrote:
> On 8/3/23 13:17, Michael S. Tsirkin wrote:
> > On Wed, Mar 08, 2023 at 08:40:42AM +0100, Philippe Mathieu-Daudé wrote:
> > > On 8/3/23 07:56, Jason Wang wrote:
> > > > On Wed, Mar 8, 2023 at 4:43 AM Philippe Mathieu-Daudé 
> > > > <philmd@linaro.org> wrote:
> > > > > 
> > > > > On 7/3/23 18:01, Peter Maydell wrote:
> > > > > > On Tue, 7 Mar 2023 at 07:08, Jason Wang <jasowang@redhat.com> wrote:
> > > > > > > 
> > > > > > > The following changes since commit 
> > > > > > > 817fd33836e73812df2f1907612b57750fcb9491:
> > > > > > > 
> > > > > > >      Merge tag 'audio-pull-request' of 
> > > > > > > https://gitlab.com/marcandre.lureau/qemu into staging (2023-03-06 
> > > > > > > 14:06:06 +0000)
> > > > > > > 
> > > > > > > are available in the git repository at:
> > > > > > > 
> > > > > > >      https://github.com/jasowang/qemu.git tags/net-pull-request
> > > > > > > 
> > > > > > > for you to fetch changes up to 
> > > > > > > c19b566a3898510ec2b3e881b3fb78614b240414:
> > > > > > > 
> > > > > > >      hw/net/eepro100: Replace DO_UPCAST(EEPRO100State) by 
> > > > > > > EEPRO100() (2023-03-07 14:55:39 +0800)
> > > > > > > 
> > > > > > > ----------------------------------------------------------------
> > > > > 
> > > > > > build-oss-fuzz failed on something involving fuzzing eepro100:
> > > > > > https://gitlab.com/qemu-project/qemu/-/jobs/3889073821
> > > > > Jason, please drop my patches. I'll look at that failure.
> > > 
> > > Before "hw/net/eepro100: Convert reset handler to DeviceReset",
> > > e100_pci_reset() is only called once from DeviceRealize _before_
> > > the device is realized.
> > > 
> > > After, 1/ it can be called multiple times and 2/ it seems to do
> > > stuffs that really belong to DeviceRealize (should be called once),
> > > in particular pci_add_capability().
> > > 
> > > I *think* it should be illegal to call pci_add_capability() _after_
> > > a device is realized. Auditing pci_add_capability(), there is only
> > > one other use before realize: amdvi_sysbus_realize() in
> > > hw/i386/amd_iommu.c.
> > 
> > Calling pci_add_capability when VM is running is likely to confuse
> > guests, yes.
> 
> Thanks for confirming. Similar pattern: msi_init().
> 
> While trying to fix that in hw/i386/amd_iommu.c I realized this device
> isn't in a good shape, almost unmaintained: 2 bugfixes in since 7 years,
> the other commits are generic API cleanups. I'll post the series and
> we can discuss that there.

Absolutely. A mix of VTD or for that matter virtio iommu and AMD CPUs
seems to work well enough that most people don't bother.
I vaguely remember spec review showed some things were hard
to support correctly with shadowing, but I don't remember
the detail (and our shadowing with VTD only works because
it matches what drivers are doing).

-- 
MST