hw/intc/arm_gicv3_cpuif: Fix virtual irq number check in icv_[dir|eoir]_write

Commit Message

Ricardo Koller July 2, 2021, 11:37 p.m. UTC

icv_eoir_write() and icv_dir_write() ignore invalid virtual IRQ numbers
(like LPIs).  The issue is that these functions check against the number
of implemented IRQs (QEMU's default is num_irq=288) which can be lower
than the maximum virtual IRQ number (1020 - 1).  The consequence is that
if a hypervisor creates an LR for an IRQ between 288 and 1020, then the
guest is unable to deactivate the resulting IRQ. Note that other
functions that deal with large IRQ numbers, like icv_iar_read, check
against 1020 and not against num_irq.

Fix the checks by using GICV3_MAXIRQ (1020) instead of the number of
implemented IRQs.

Signed-off-by: Ricardo Koller <[e-mail]>
---
 hw/intc/arm_gicv3_cpuif.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

Comments

Peter Maydell July 5, 2021, 1:32 p.m. UTC | #1

On Sat, 3 Jul 2021 at 00:37, Ricardo Koller <[e-mail]> wrote:
>
> icv_eoir_write() and icv_dir_write() ignore invalid virtual IRQ numbers
> (like LPIs).  The issue is that these functions check against the number
> of implemented IRQs (QEMU's default is num_irq=288) which can be lower
> than the maximum virtual IRQ number (1020 - 1).  The consequence is that
> if a hypervisor creates an LR for an IRQ between 288 and 1020, then the
> guest is unable to deactivate the resulting IRQ. Note that other
> functions that deal with large IRQ numbers, like icv_iar_read, check
> against 1020 and not against num_irq.
>
> Fix the checks by using GICV3_MAXIRQ (1020) instead of the number of
> implemented IRQs.
>
> Signed-off-by: Ricardo Koller <[e-mail]>
> ---
>  hw/intc/arm_gicv3_cpuif.c | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)



Applied to target-arm.next, thanks.

-- PMM

Patch

diff --git a/hw/intc/arm_gicv3_cpuif.c b/hw/intc/arm_gicv3_cpuif.c
index 3e0641aff9..a032d505f5 100644
--- a/hw/intc/arm_gicv3_cpuif.c
+++ b/hw/intc/arm_gicv3_cpuif.c
@@ -1227,7 +1227,7 @@  static void icv_dir_write(CPUARMState *env, const ARMCPRegInfo *ri,
 
     trace_gicv3_icv_dir_write(gicv3_redist_affid(cs), value);
 
-    if (irq >= cs->gic->num_irq) {
+    if (irq >= GICV3_MAXIRQ) {
         /* Also catches special interrupt numbers and LPIs */
         return;
     }
@@ -1262,7 +1262,7 @@  static void icv_eoir_write(CPUARMState *env, const ARMCPRegInfo *ri,
     trace_gicv3_icv_eoir_write(ri->crm == 8 ? 0 : 1,
                                gicv3_redist_affid(cs), value);
 
-    if (irq >= cs->gic->num_irq) {
+    if (irq >= GICV3_MAXIRQ) {
         /* Also catches special interrupt numbers and LPIs */
         return;
     }