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[PATCH 11/14] hw/intc/arm_gicv3_its: Make GITS_BASER<n> RAZ/WI for unimp
From: |
Peter Maydell |
Subject: |
[PATCH 11/14] hw/intc/arm_gicv3_its: Make GITS_BASER<n> RAZ/WI for unimplemented registers |
Date: |
Sat, 22 Jan 2022 18:24:41 +0000 |
The ITS has a bank of 8 GITS_BASER<n> registers, which allow the
guest to specify the base address of various data tables. Each
register has a read-only type field indicating which table it is for
and a read-write field where the guest can write in the base address
(among other things). We currently allow the guest to write the
writeable fields for all eight registers, even if the type field is 0
indicating "Unimplemented". This means the guest can provoke QEMU
into asserting by writing an address into one of these unimplemented
base registers, which bypasses the "if (!value) continue" check in
extract_table_params() and lets us hit the assertion that the type
field is one of the permitted table types.
Prevent the assertion by not allowing the guest to write to the
unimplemented base registers. This means their value will remain 0
and extract_table_params() will ignore them.
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
---
hw/intc/arm_gicv3_its.c | 8 ++++++++
1 file changed, 8 insertions(+)
diff --git a/hw/intc/arm_gicv3_its.c b/hw/intc/arm_gicv3_its.c
index b17f2631269..237198845d7 100644
--- a/hw/intc/arm_gicv3_its.c
+++ b/hw/intc/arm_gicv3_its.c
@@ -929,6 +929,10 @@ static bool its_writel(GICv3ITSState *s, hwaddr offset,
if (!(s->ctlr & R_GITS_CTLR_ENABLED_MASK)) {
index = (offset - GITS_BASER) / 8;
+ if (s->baser[index] == 0) {
+ /* Unimplemented GITS_BASERn: RAZ/WI */
+ break;
+ }
if (offset & 7) {
value <<= 32;
value &= ~GITS_BASER_RO_MASK;
@@ -1025,6 +1029,10 @@ static bool its_writell(GICv3ITSState *s, hwaddr offset,
*/
if (!(s->ctlr & R_GITS_CTLR_ENABLED_MASK)) {
index = (offset - GITS_BASER) / 8;
+ if (s->baser[index] == 0) {
+ /* Unimplemented GITS_BASERn: RAZ/WI */
+ break;
+ }
s->baser[index] &= GITS_BASER_RO_MASK;
s->baser[index] |= (value & ~GITS_BASER_RO_MASK);
}
--
2.25.1
- Re: [PATCH 02/14] hw/intc/arm_gicv3_its: Add tracepoints, (continued)
- [PATCH 07/14] hw/intc/arm_gicv3_its: Sort ITS command list into numeric order, Peter Maydell, 2022/01/22
- [PATCH 04/14] hw/intc/arm_gicv3_its: Don't clear GITS_CREADR when GITS_CTLR.ENABLED is set, Peter Maydell, 2022/01/22
- [PATCH 10/14] hw/intc/arm_gicv3_its: Provide read accessor for translation_ops, Peter Maydell, 2022/01/22
- [PATCH 11/14] hw/intc/arm_gicv3_its: Make GITS_BASER<n> RAZ/WI for unimplemented registers,
Peter Maydell <=
- [PATCH 12/14] hw/intc/arm_gicv3_its: Check table bounds against correct limit, Peter Maydell, 2022/01/22
- [PATCH 14/14] hw/intc/arm_gicv3_its: Implement MOVI, Peter Maydell, 2022/01/22
- [PATCH 03/14] hw/intc/arm_gicv3: Initialise dma_as in GIC, not ITS, Peter Maydell, 2022/01/22