[PATCH v5 13/22] KVM: arm64: vgic-its: Check the device id matches TYPER DEVBITS range

[Eric Auger]

On MAPD we currently check the device id can be stored in the device table.
Let's first check it can be encoded within the range defined by TYPER
DEVBITS.

Signed-off-by: Eric Auger <eric.auger at redhat.com>

---

v4 -> v5:
- use GIC_ENCODE_SZ macro

v3 -> v4:
- VITS_TYPER_DEVBITS set to 16 for homogeneity
- use BIT_ULL
---
 virt/kvm/arm/vgic/vgic-its.c | 10 +++++++---
 1 file changed, 7 insertions(+), 3 deletions(-)

diff --git a/virt/kvm/arm/vgic/vgic-its.c b/virt/kvm/arm/vgic/vgic-its.c
index 757598d..de1ed6d 100644
--- a/virt/kvm/arm/vgic/vgic-its.c
+++ b/virt/kvm/arm/vgic/vgic-its.c
@@ -194,6 +194,7 @@ static struct its_ite *find_ite(struct vgic_its *its, u32 device_id,
 #define GIC_LPI_OFFSET 8192
 
 #define VITS_TYPER_IDBITS 16
+#define VITS_TYPER_DEVBITS 16
 
 /*
  * Finds and returns a collection in the ITS collection table.
@@ -394,7 +395,7 @@ static unsigned long vgic_mmio_read_its_typer(struct kvm *kvm,
 	 * To avoid memory waste in the guest, we keep the number of IDBits and
 	 * DevBits low - as least for the time being.
 	 */
-	reg |= 0x0f << GITS_TYPER_DEVBITS_SHIFT;
+	reg |= GIC_ENCODE_SZ(VITS_TYPER_DEVBITS, 5) << GITS_TYPER_DEVBITS_SHIFT;
 	reg |= GIC_ENCODE_SZ(VITS_TYPER_IDBITS, 5) << GITS_TYPER_IDBITS_SHIFT;
 	reg |= GIC_ENCODE_SZ(abi->ite_esz, 4) << GITS_TYPER_ITT_ENTRY_SIZE_SHIFT;
 
@@ -639,10 +640,10 @@ static int vgic_its_cmd_handle_movi(struct kvm *kvm, struct vgic_its *its,
  * Check whether an ID can be stored into the corresponding guest table.
  * For a direct table this is pretty easy, but gets a bit nasty for
  * indirect tables. We check whether the resulting guest physical address
- * is actually valid (covered by a memslot and guest accessbible).
+ * is actually valid (covered by a memslot and guest accessible).
  * For this we have to read the respective first level entry.
  */
-static bool vgic_its_check_id(struct vgic_its *its, u64 baser, int id)
+static bool vgic_its_check_id(struct vgic_its *its, u64 baser, u32 id)
 {
 	int l1_tbl_size = GITS_BASER_NR_PAGES(baser) * SZ_64K;
 	int index;
@@ -650,6 +651,9 @@ static bool vgic_its_check_id(struct vgic_its *its, u64 baser, int id)
 	gfn_t gfn;
 	int esz = GITS_BASER_ENTRY_SIZE(baser);
 
+	if (id >= BIT_ULL(VITS_TYPER_DEVBITS))
+		return false;
+
 	if (!(baser & GITS_BASER_INDIRECT)) {
 		phys_addr_t addr;
 
-- 
2.5.5