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, 37 insertions, 23 deletions

diff --git a/usr.sbin/bhyve/pci_passthru.c b/usr.sbin/bhyve/pci_passthru.c
index 131f08a..08a9a58 100644
--- a/usr.sbin/bhyve/pci_passthru.c
+++ b/usr.sbin/bhyve/pci_passthru.c
@@ -355,14 +355,18 @@ msix_table_write(struct vmctx *ctx, int vcpu, struct passthru_softc *sc,
 static int
 init_msix_table(struct vmctx *ctx, struct passthru_softc *sc, uint64_t base)
 {
-	int idx;
-	size_t table_size;
+	int b, s, f;
+	int error, idx;
+	size_t len, remaining, table_size;
 	vm_paddr_t start;
-	size_t len;
 	struct pci_devinst *pi = sc->psc_pi;
 
 	assert(pci_msix_table_bar(pi) >= 0 && pci_msix_pba_bar(pi) >= 0);
 
+	b = sc->psc_sel.pc_bus;
+	s = sc->psc_sel.pc_dev;
+	f = sc->psc_sel.pc_func;
+
 	/* 
 	 * If the MSI-X table BAR maps memory intended for
 	 * other uses, it is at least assured that the table 
@@ -372,34 +376,44 @@ init_msix_table(struct vmctx *ctx, struct passthru_softc *sc, uint64_t base)
 	if (pi->pi_msix.pba_bar == pi->pi_msix.table_bar && 
 	    ((pi->pi_msix.pba_offset - pi->pi_msix.table_offset) < 4096)) {
 		/* Need to also emulate the PBA, not supported yet */
-		printf("Unsupported MSI-X configuration: %d/%d/%d\n",
-		       sc->psc_sel.pc_bus, sc->psc_sel.pc_dev,
-		       sc->psc_sel.pc_func);
+		printf("Unsupported MSI-X configuration: %d/%d/%d\n", b, s, f);
 		return (-1);
 	}
 
-	/* 
-	 * May need to split the BAR into 3 regions:
-	 * Before the MSI-X table, the MSI-X table, and after it
-	 * XXX for now, assume that the table is not in the middle
-	 */
+	/* Compute the MSI-X table size */
 	table_size = pi->pi_msix.table_count * MSIX_TABLE_ENTRY_SIZE;
+	table_size = roundup2(table_size, 4096);
+
 	idx = pi->pi_msix.table_bar;
+	start = pi->pi_bar[idx].addr;
+	remaining = pi->pi_bar[idx].size;
 
-	/* Round up to page size */
-	table_size = roundup2(table_size, 4096);
-	if (pi->pi_msix.table_offset == 0) {		
-		/* Map everything after the MSI-X table */
-		start = pi->pi_bar[idx].addr + table_size;
-		len = pi->pi_bar[idx].size - table_size;
-	} else {
-                /* Map everything before the MSI-X table */
-		start = pi->pi_bar[idx].addr;
+	/* Map everything before the MSI-X table */
+	if (pi->pi_msix.table_offset > 0) {
 		len = pi->pi_msix.table_offset;
+		error = vm_map_pptdev_mmio(ctx, b, s, f, start, len, base);
+		if (error)
+			return (error);
+
+		base += len;
+		start += len;
+		remaining -= len;
 	}
-	return (vm_map_pptdev_mmio(ctx, sc->psc_sel.pc_bus, 
-				   sc->psc_sel.pc_dev, sc->psc_sel.pc_func, 
-				   start, len, base + table_size));
+
+	/* Skip the MSI-X table */
+	base += table_size;
+	start += table_size;
+	remaining -= table_size;
+
+	/* Map everything beyond the end of the MSI-X table */
+	if (remaining > 0) {
+		len = remaining;
+		error = vm_map_pptdev_mmio(ctx, b, s, f, start, len, base);
+		if (error)
+			return (error);
+	}
+
+	return (0);
 }
 
 static int