From 6a52209f9cf5dea89a1a7e1ed4e84f42cbb49172 Mon Sep 17 00:00:00 2001 From: Neel Natu Date: Tue, 27 Aug 2013 16:50:48 +0000 Subject: [PATCH] Allow single byte reads of the emulated MSI-X tables. This is not required by the PCI specification but needed to dump MMIO space from "ddb" in the guest. --- usr.sbin/bhyve/pci_emul.c | 12 +++++++++--- 1 file changed, 9 insertions(+), 3 deletions(-) diff --git a/usr.sbin/bhyve/pci_emul.c b/usr.sbin/bhyve/pci_emul.c index 005e8b139f3..626dfdf0144 100644 --- a/usr.sbin/bhyve/pci_emul.c +++ b/usr.sbin/bhyve/pci_emul.c @@ -245,8 +245,12 @@ pci_emul_msix_tread(struct pci_devinst *pi, uint64_t offset, int size) int tab_index; uint64_t retval = ~0; - /* support only 4 or 8 byte reads */ - if (size != 4 && size != 8) + /* + * The PCI standard only allows 4 and 8 byte accesses to the MSI-X + * table but we also allow 1 byte access to accomodate reads from + * ddb. + */ + if (size != 1 && size != 4 && size != 8) return (retval); msix_entry_offset = offset % MSIX_TABLE_ENTRY_SIZE; @@ -263,7 +267,9 @@ pci_emul_msix_tread(struct pci_devinst *pi, uint64_t offset, int size) dest = (char *)(pi->pi_msix.table + tab_index); dest += msix_entry_offset; - if (size == 4) + if (size == 1) + retval = *((uint8_t *)dest); + else if (size == 4) retval = *((uint32_t *)dest); else retval = *((uint64_t *)dest);