Fix a broken assumption in the passthru implementation that the MSI-X table

can only be located at the beginning or the end of the BAR.

If the MSI-table is located in the middle of a BAR then we will split the
BAR into two and create two mappings - one before the table and one after
the table - leaving a hole in place of the table so accesses to it can be
trapped and emulated.

Obtained from:	NetApp

1 files changed, 10 insertions, 1 deletions

diff --git a/sys/amd64/vmm/io/ppt.c b/sys/amd64/vmm/io/ppt.c
index d3ec8d1..4a05985 100644
--- a/sys/amd64/vmm/io/ppt.c
+++ b/sys/amd64/vmm/io/ppt.c
@@ -56,9 +56,18 @@ __FBSDID("$FreeBSD$");
 /* XXX locking */
 
 #define	MAX_PPTDEVS	(sizeof(pptdevs) / sizeof(pptdevs[0]))
-#define	MAX_MMIOSEGS	(PCIR_MAX_BAR_0 + 1)
 #define	MAX_MSIMSGS	32
 
+/*
+ * If the MSI-X table is located in the middle of a BAR then that MMIO
+ * region gets split into two segments - one segment above the MSI-X table
+ * and the other segment below the MSI-X table - with a hole in place of
+ * the MSI-X table so accesses to it can be trapped and emulated.
+ *
+ * So, allocate a MMIO segment for each BAR register + 1 additional segment.
+ */
+#define	MAX_MMIOSEGS	((PCIR_MAX_BAR_0 + 1) + 1)
+
 MALLOC_DEFINE(M_PPTMSIX, "pptmsix", "Passthru MSI-X resources");
 
 struct pptintr_arg {				/* pptintr(pptintr_arg) */