Author: grehan
Date: Wed Oct 9 23:53:21 2013
New Revision: 256248
URL: http://svnweb.freebsd.org/changeset/base/256248
Log:
Allow a 4-byte write to PCI config space to overlap
the 2 read-only bytes at the start of a PCI capability.
This is the sequence that OpenBSD uses when enabling
MSI interrupts, and works fine on real h/w.
In bhyve, convert the 4 byte write to a 2-byte write to
the r/w area past the first 2 r/o bytes of a capability.
Reviewed by: neel
Approved by: re@ (blanket)
Modified:
head/usr.sbin/bhyve/pci_emul.c
Modified: head/usr.sbin/bhyve/pci_emul.c
==============================================================================
--- head/usr.sbin/bhyve/pci_emul.c Wed Oct 9 22:10:03 2013
(r256247)
+++ head/usr.sbin/bhyve/pci_emul.c Wed Oct 9 23:53:21 2013
(r256248)
@@ -941,10 +941,19 @@ pci_emul_capwrite(struct pci_devinst *pi
assert(offset >= capoff);
/*
- * Capability ID and Next Capability Pointer are readonly
+ * Capability ID and Next Capability Pointer are readonly.
+ * However, some o/s's do 4-byte writes that include these.
+ * For this case, trim the write back to 2 bytes and adjust
+ * the data.
*/
- if (offset == capoff || offset == capoff + 1)
- return;
+ if (offset == capoff || offset == capoff + 1) {
+ if (offset == capoff && bytes == 4) {
+ bytes = 2;
+ offset += 2;
+ val >>= 16;
+ } else
+ return;
+ }
switch (capid) {
case PCIY_MSI:
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