Re: [PATCH v3 3/9] vfio: add quirk device write method
On Fri, 17 Jul 2020 16:57:40 +0100 Peter Maydell wrote: > On Fri, 17 Jul 2020 at 16:54, Alex Williamson > wrote: > > > > On Thu, 16 Jul 2020 18:46:33 +0100 > > Peter Maydell wrote: > > > > > Alex (Williamson) -- as the vfio maintainer, do you have a view > > > on whether we should be logging write accesses to port 0x3c3 > > > here as guest-errors or unimplemented-QEMU-functionality? > > > > > > Guest-error seems plausible to me, anyway. > > > > I believe the intention was that writes would be dropped, so if this > > generates logging that is going to cause users to file bugs, that would > > be undesirable. Thanks, > > It will only log if the user explicitly turns on "log things the > guest does which are bugs in it, like writing to read-only > registers" (with the '-d guest_errors' option). IIRC, this quirk is based on observation more so than an actual spec, so whether a log of such an event is interpreted as a guest error or an emulation error might be up for debate. Aside from that nit, and lack of bandwidth to research how hardware handles writes, Acked-by: Alex Williamson Thanks, Alex
Re: [PATCH v3 3/9] vfio: add quirk device write method
On Fri, 17 Jul 2020 at 16:54, Alex Williamson wrote: > > On Thu, 16 Jul 2020 18:46:33 +0100 > Peter Maydell wrote: > > > Alex (Williamson) -- as the vfio maintainer, do you have a view > > on whether we should be logging write accesses to port 0x3c3 > > here as guest-errors or unimplemented-QEMU-functionality? > > > > Guest-error seems plausible to me, anyway. > > I believe the intention was that writes would be dropped, so if this > generates logging that is going to cause users to file bugs, that would > be undesirable. Thanks, It will only log if the user explicitly turns on "log things the guest does which are bugs in it, like writing to read-only registers" (with the '-d guest_errors' option). thanks -- PMM
Re: [PATCH v3 3/9] vfio: add quirk device write method
On Thu, 16 Jul 2020 18:46:33 +0100
Peter Maydell wrote:
> On Tue, 30 Jun 2020 at 13:30, P J P wrote:
> >
> > From: Prasad J Pandit
> >
> > Add vfio quirk device mmio write method to avoid NULL pointer
> > dereference issue.
> >
> > Reported-by: Lei Sun
> > Reviewed-by: Li Qiang
> > Signed-off-by: Prasad J Pandit
> > ---
> > hw/vfio/pci-quirks.c | 8
> > 1 file changed, 8 insertions(+)
> >
> > Update v3: Add Reviewed-by: ...
> > -> https://lists.gnu.org/archive/html/qemu-devel/2020-06/msg09406.html
> >
> > diff --git a/hw/vfio/pci-quirks.c b/hw/vfio/pci-quirks.c
> > index d304c81148..cc6d5dbc23 100644
> > --- a/hw/vfio/pci-quirks.c
> > +++ b/hw/vfio/pci-quirks.c
> > @@ -14,6 +14,7 @@
> > #include "config-devices.h"
> > #include "exec/memop.h"
> > #include "qemu/units.h"
> > +#include "qemu/log.h"
> > #include "qemu/error-report.h"
> > #include "qemu/main-loop.h"
> > #include "qemu/module.h"
> > @@ -264,8 +265,15 @@ static uint64_t vfio_ati_3c3_quirk_read(void *opaque,
> > return data;
> > }
> >
> > +static void vfio_ati_3c3_quirk_write(void *opaque, hwaddr addr,
> > +uint64_t data, unsigned size)
> > +{
> > +qemu_log_mask(LOG_GUEST_ERROR, "%s not implemented\n", __func__);
> > +}
> > +
> > static const MemoryRegionOps vfio_ati_3c3_quirk = {
> > .read = vfio_ati_3c3_quirk_read,
> > +.write = vfio_ati_3c3_quirk_write,
> > .endianness = DEVICE_LITTLE_ENDIAN,
> > };
>
>
> Alex (Williamson) -- as the vfio maintainer, do you have a view
> on whether we should be logging write accesses to port 0x3c3
> here as guest-errors or unimplemented-QEMU-functionality?
>
> Guest-error seems plausible to me, anyway.
I believe the intention was that writes would be dropped, so if this
generates logging that is going to cause users to file bugs, that would
be undesirable. Thanks,
Alex
Re: [PATCH v3 3/9] vfio: add quirk device write method
On Tue, 30 Jun 2020 at 13:30, P J P wrote:
>
> From: Prasad J Pandit
>
> Add vfio quirk device mmio write method to avoid NULL pointer
> dereference issue.
>
> Reported-by: Lei Sun
> Reviewed-by: Li Qiang
> Signed-off-by: Prasad J Pandit
> ---
> hw/vfio/pci-quirks.c | 8
> 1 file changed, 8 insertions(+)
>
> Update v3: Add Reviewed-by: ...
> -> https://lists.gnu.org/archive/html/qemu-devel/2020-06/msg09406.html
>
> diff --git a/hw/vfio/pci-quirks.c b/hw/vfio/pci-quirks.c
> index d304c81148..cc6d5dbc23 100644
> --- a/hw/vfio/pci-quirks.c
> +++ b/hw/vfio/pci-quirks.c
> @@ -14,6 +14,7 @@
> #include "config-devices.h"
> #include "exec/memop.h"
> #include "qemu/units.h"
> +#include "qemu/log.h"
> #include "qemu/error-report.h"
> #include "qemu/main-loop.h"
> #include "qemu/module.h"
> @@ -264,8 +265,15 @@ static uint64_t vfio_ati_3c3_quirk_read(void *opaque,
> return data;
> }
>
> +static void vfio_ati_3c3_quirk_write(void *opaque, hwaddr addr,
> +uint64_t data, unsigned size)
> +{
> +qemu_log_mask(LOG_GUEST_ERROR, "%s not implemented\n", __func__);
> +}
> +
> static const MemoryRegionOps vfio_ati_3c3_quirk = {
> .read = vfio_ati_3c3_quirk_read,
> +.write = vfio_ati_3c3_quirk_write,
> .endianness = DEVICE_LITTLE_ENDIAN,
> };
Alex (Williamson) -- as the vfio maintainer, do you have a view
on whether we should be logging write accesses to port 0x3c3
here as guest-errors or unimplemented-QEMU-functionality?
Guest-error seems plausible to me, anyway.
Reviewed-by: Peter Maydell
thanks
-- PMM
[PATCH v3 3/9] vfio: add quirk device write method
From: Prasad J Pandit
Add vfio quirk device mmio write method to avoid NULL pointer
dereference issue.
Reported-by: Lei Sun
Reviewed-by: Li Qiang
Signed-off-by: Prasad J Pandit
---
hw/vfio/pci-quirks.c | 8
1 file changed, 8 insertions(+)
Update v3: Add Reviewed-by: ...
-> https://lists.gnu.org/archive/html/qemu-devel/2020-06/msg09406.html
diff --git a/hw/vfio/pci-quirks.c b/hw/vfio/pci-quirks.c
index d304c81148..cc6d5dbc23 100644
--- a/hw/vfio/pci-quirks.c
+++ b/hw/vfio/pci-quirks.c
@@ -14,6 +14,7 @@
#include "config-devices.h"
#include "exec/memop.h"
#include "qemu/units.h"
+#include "qemu/log.h"
#include "qemu/error-report.h"
#include "qemu/main-loop.h"
#include "qemu/module.h"
@@ -264,8 +265,15 @@ static uint64_t vfio_ati_3c3_quirk_read(void *opaque,
return data;
}
+static void vfio_ati_3c3_quirk_write(void *opaque, hwaddr addr,
+uint64_t data, unsigned size)
+{
+qemu_log_mask(LOG_GUEST_ERROR, "%s not implemented\n", __func__);
+}
+
static const MemoryRegionOps vfio_ati_3c3_quirk = {
.read = vfio_ati_3c3_quirk_read,
+.write = vfio_ati_3c3_quirk_write,
.endianness = DEVICE_LITTLE_ENDIAN,
};
--
2.26.2
