From 24be3f513f218c83acd6733097bd5b3ce8aed451 Mon Sep 17 00:00:00 2001 From: John Baldwin Date: Wed, 5 Jun 2019 19:29:02 +0000 Subject: [PATCH] Don't simulate PBA access if the PBA is in a separate BAR. 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 --- usr.sbin/bhyve/pci_passthru.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/usr.sbin/bhyve/pci_passthru.c b/usr.sbin/bhyve/pci_passthru.c index 0e843bd13747..785da84244df 100644 --- a/usr.sbin/bhyve/pci_passthru.c +++ b/usr.sbin/bhyve/pci_passthru.c @@ -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: