Hi Phil,
On 6/16/25 2:59 AM, Philippe Mathieu-Daudé wrote:
Hi Alejandro,
On 12/6/25 22:59, Alejandro Jimenez wrote:
Hi Ethan,
On 6/12/25 4:36 AM, Ethan MILON wrote:
Hi,
Is this series the right place to include the following minor fix?
I would defer this change for two reasons:
1) This series has been reviewed and tested already. I was hoping it
would be included on the Jun 1st pull but I sent v3 too late for that.
I think it is ready so I would like to leave it as is unless there are
any objections ...
diff --git a/hw/i386/amd_iommu.c b/hw/i386/amd_iommu.c
index 0775c..18d30e1 100644
--- a/hw/i386/amd_iommu.c
+++ b/hw/i386/amd_iommu.c
@@ -140,7 +140,7 @@ static void amdvi_writeq(AMDVIState *s, hwaddr addr,
uint64_t val)
{
uint64_t romask = ldq_le_p(&s->romask[addr]);
uint64_t w1cmask = ldq_le_p(&s->w1cmask[addr]);
- uint32_t oldval = ldq_le_p(&s->mmior[addr]);
+ uint64_t oldval = ldq_le_p(&s->mmior[addr]);
stq_le_p(&s->mmior[addr],
((oldval & romask) | (val & ~romask)) & ~(val & w1cmask));
}
This corrects the type of oldval to match the return type of ldq_le_p().
2) This fix is needed, but it is likely better as part of additional
changes that are needed to cleanup/fix the XTSup support. i.e. there
are unhandled writes to the 0x170, 0x178, and 0x180 MMIO offsets, and
those depend on MMIO 0x18[IntCapXTEn]=1. I think the truncation of
oldval that you found is causing XTEn and IntCapXTEn bits on the
control registers to be ignored, but ultimately things are not broken
enough (yet).
I agree with Ethan it is better to avoid hidden truncation, because it
just makes debugging experience harder.
I agree that Ethan found a bug that must be fixed. I am answering his
initial question of whether this series is the right place to fix it by
pointing out that this bug uncovers that there is more to do than just
fixing this specific error, and it could be included in a series to
address those larger problems that I mentioned above.
On the other hand, it is probably better just to fix this specific bug
now since it is simple enough, which is why I asked Ethan to send a
commit and I will add it (he should get credit)
If this is the expected behavior, better add a comment, or use
extract64() which makes the truncation explicit.
It is not the expected behavior, the truncation is a bug. It doesn't yet
cause any issues because amdvi_writeq() is currently only called to
handle MMIO writes for a few offsets/register, mostly to
AMDVI_MMIO_CONTROL, and the romask for the offset is 0. This means that
the bug doesn't really change the value that is ultimately written to
the emulated MMIO register, but it could cause problems in the future.
Thank you,
Alejandro
Regards,
Phil.
In other words, I think there is a lot more work to do in here, and it
is something I am looking into.
I suspect Vasant might have spotted this problem already, so he might
even have some fixes queued up...
That being said, if you want to send a patch with your S-b I'll add it
to this series.
Alejandro
Thanks,
Ethan
On 5/29/25 9:30 PM, Alejandro Jimenez wrote:
Caution: External email. Do not open attachments or click links,
unless this email comes from a known sender and you know the content
is safe.
The main reason for sending this new revision so soon is that v2
included a
duplicated [PATCH 5/7]. I fixed a typo in the commit subject and missed
removing the old patch. Apologies for the mistake.
Additional changes in v3:
- Fixed typo on [PATCH 1/7] subject line (s/Miscellanous/
Miscellaneous/).
- Added 'Fixes:' tag to [PATCH 5/7].
- Added Vasant's R-b to patches 4,5,7.
Thank you,
Alejandro
v2:
https://lore.kernel.org/qemu-devel/20250528221725.3554040-1-
alejandro.j.jime...@oracle.com/
v1:
https://lore.kernel.org/all/20250311152446.45086-1-
alejandro.j.jime...@oracle.com/
Alejandro Jimenez (7):
amd_iommu: Fix Miscellaneous Information Register 0 offsets
amd_iommu: Fix Device ID decoding for INVALIDATE_IOTLB_PAGES command
amd_iommu: Update bitmasks representing DTE reserved fields
amd_iommu: Fix masks for various IOMMU MMIO Registers
amd_iommu: Fix mask to retrieve Interrupt Table Root Pointer from
DTE
amd_iommu: Fix the calculation for Device Table size
amd_iommu: Remove duplicated definitions
hw/i386/amd_iommu.c | 15 ++++++------
hw/i386/amd_iommu.h | 59 +++++++++++++++++++++
+-----------------------
2 files changed, 37 insertions(+), 37 deletions(-)
base-commit: 80db93b2b88f9b3ed8927ae7ac74ca30e643a83e
--
2.43.5
