bhyve: Validate host PAs used to map passthrough BARs.

Reject attempts to map host physical address ranges that are not
subsets of a passthrough device's BAR into a guest.

Reviewed by:	markj, emaste
MFC after:	1 week
Sponsored by:	The FreeBSD Foundation
Differential Revision:	https://reviews.freebsd.org/D36238

1 files changed, 24 insertions, 0 deletions

diff --git a/sys/amd64/vmm/io/ppt.c b/sys/amd64/vmm/io/ppt.c
index 6bcd8f78bbab..6621c0ba2996 100644
--- a/sys/amd64/vmm/io/ppt.c
+++ b/sys/amd64/vmm/io/ppt.c
@@ -439,6 +439,23 @@ ppt_unassign_all(struct vm *vm)
 	return (0);
 }
 
+static bool
+ppt_valid_bar_mapping(struct pptdev *ppt, vm_paddr_t hpa, size_t len)
+{
+	struct pci_map *pm;
+	pci_addr_t base, size;
+
+	for (pm = pci_first_bar(ppt->dev); pm != NULL; pm = pci_next_bar(pm)) {
+		if (!PCI_BAR_MEM(pm->pm_value))
+			continue;
+		base = pm->pm_value & PCIM_BAR_MEM_BASE;
+		size = (pci_addr_t)1 << pm->pm_size;
+		if (hpa >= base && hpa + len <= base + size)
+			return (true);
+	}
+	return (false);
+}
+
 int
 ppt_map_mmio(struct vm *vm, int bus, int slot, int func,
 	     vm_paddr_t gpa, size_t len, vm_paddr_t hpa)
@@ -447,10 +464,17 @@ ppt_map_mmio(struct vm *vm, int bus, int slot, int func,
 	struct pptseg *seg;
 	struct pptdev *ppt;
 
+	if (len % PAGE_SIZE != 0 || len == 0 || gpa % PAGE_SIZE != 0 ||
+	    hpa % PAGE_SIZE != 0 || gpa + len < gpa || hpa + len < hpa)
+		return (EINVAL);
+
 	error = ppt_find(vm, bus, slot, func, &ppt);
 	if (error)
 		return (error);
 
+	if (!ppt_valid_bar_mapping(ppt, hpa, len))
+		return (EINVAL);
+
 	for (i = 0; i < MAX_MMIOSEGS; i++) {
 		seg = &ppt->mmio[i];
 		if (seg->len == 0) {