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Don't simulate PBA access if the PBA is in a separate BAR.

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bhyve has to virtualize the MSI-X table to trap reads and writes to
that table and map those to virtual interrupts that it maps real host
interrupts on to.  For the pending-bit-array (PBA), bhyve passes
accesses from the guest directly to the hardware.

bhyve's virtualization of the MSI-X table is done by intercepting all
reads and writes to the BAR holding the MSI-X table.  However, if the
PBA is stored in the same BAR as the MSI-X table, accesses to the PBA
portion of this BAR have to be forwarded to the real BAR.

However, in the case that the PBA was stored in a separate BAR and
it's offset in that separate BAR overlapped with the portion of the
MSI-X table BAR that the table used, the handlers for the table BAR
would incorrectly think that some accesses were PBA reads and writes.
This caused a crash in bhyve when it indirected a NULL pointer.  Fix
this case by never trying to handle PBA access if the PBA lives in a
separate BAR.

Reported by:	gallatin
Tested by:	gallatin
Reviewed by:	markj, Patrick Mooney
MFC after:	1 week
Differential Revision:	https://reviews.freebsd.org/D20523
This commit is contained in:
John Baldwin 2019-06-05 19:29:02 +00:00
parent 25082bd7d2
commit 24be3f513f
Notes: svn2git 2020-12-20 02:59:44 +00:00 
svn path=/head/; revision=348694
1 changed files with 2 additions and 2 deletions
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4
usr.sbin/bhyve/pci_passthru.c
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@ -295,7 +295,7 @@ msix_table_read(struct passthru_softc *sc, uint64_t offset, int size)
int index;
pi = sc->psc_pi;
if (offset >= pi->pi_msix.pba_offset &&
if (pi->pi_msix.pba_page != NULL && offset >= pi->pi_msix.pba_offset &&
offset < pi->pi_msix.pba_offset + pi->pi_msix.pba_size) {
switch(size) {
case 1:
@ -374,7 +374,7 @@ msix_table_write(struct vmctx *ctx, int vcpu, struct passthru_softc *sc,
int index;
pi = sc->psc_pi;
if (offset >= pi->pi_msix.pba_offset &&
if (pi->pi_msix.pba_page != NULL && offset >= pi->pi_msix.pba_offset &&
offset < pi->pi_msix.pba_offset + pi->pi_msix.pba_size) {
switch(size) {
case 1: