On Fri, 6 Feb 2026, Mark Johnston wrote:
The branch main has been updated by markj:
URL:
https://cgit.FreeBSD.org/src/commit/?id=36b855f1892575cbfe1cd5455b989bfc8ae07502
commit 36b855f1892575cbfe1cd5455b989bfc8ae07502
Author: Mark Johnston <[email protected]>
AuthorDate: 2026-02-06 15:29:22 +0000
Commit: Mark Johnston <[email protected]>
CommitDate: 2026-02-06 15:38:51 +0000
amd64/vmm: Lock global PCI passthrough structures
There is a global list of ppt-claimed devices, accessed via several
vmm ioctls. The ioctls are locked by per-VM locks, but this isn't
sufficient to prevent multiple VMs from trying to bind a given device.
Add a sleepable lock and use that to synchronize all access to ppt
devices.
Reviewed by: corvink, jhb
MFC after: 2 weeks
Differential Revision: https://reviews.freebsd.org/D55065
---
sys/amd64/vmm/io/ppt.c | 162 +++++++++++++++++++++++++++++++++----------------
1 file changed, 111 insertions(+), 51 deletions(-)
diff --git a/sys/amd64/vmm/io/ppt.c b/sys/amd64/vmm/io/ppt.c
index 6feac5dcbbed..b522e18e3b24 100644
--- a/sys/amd64/vmm/io/ppt.c
+++ b/sys/amd64/vmm/io/ppt.c
...
int
@@ -529,10 +558,12 @@ ppt_unmap_mmio(struct vm *vm, int bus, int slot, int func,
struct pptseg *seg;
struct pptdev *ppt;
+ PPT_LOCK();
error = ppt_find(vm, bus, slot, func, &ppt);
if (error)
- return (error);
+ goto out;
+ error = ENOENT;
for (i = 0; i < MAX_MMIOSEGS; i++) {
seg = &ppt->mmio[i];
if (seg->gpa == gpa && seg->len == len) {
@@ -541,9 +572,11 @@ ppt_unmap_mmio(struct vm *vm, int bus, int slot, int func,
seg->gpa = 0;
seg->len = 0;
}
- return (error);
+ break;
}
}
+out:
+ PPT_UNLOCK();
return (ENOENT);
}
There's a bug here. That should be return (error). That's been breaking
pci passthru since February. I cannot imagine how no one noticed this in
3 months?
/bz
--
Bjoern A. Zeeb r15:7
