Commit Message

Damien Hedde Dec. 7, 2021, 9:29 a.m. UTC

Subject: [PATCH for 6.2?] gicv3: fix ICH_MISR's LRENP computation

According to the "Arm Generic Interrupt Controller Architecture
Specification GIC architecture version 3 and 4" (version G: page 345
for aarch64 or 509 for aarch32):
LRENP bit of ICH_MISR is set when ICH_HCR.LRENPIE==1 and
ICH_HCR.EOIcount is non-zero.

When only LRENPIE was set (and EOI count was zero), the LRENP bit was
wrongly set and MISR value was wrong.

As an additional consequence, if an hypervisor set ICH_HCR.LRENPIE,
the maintenance interrupt was constantly fired. It happens since patch
9cee1efe92 ("hw/intc: Set GIC maintenance interrupt level to only 0 or 1")
which fixed another bug about maintenance interrupt (most significant
bits of misr, including this one, were ignored in the interrupt trigger).

Fixes: 83f036fe3d ("hw/intc/arm_gicv3: Add accessors for ICH_ system registers")
Signed-off-by: Damien Hedde <[e-mail]>
---
The gic doc is available here:
https://developer.arm.com/documentation/ihi0069/g
---
 hw/intc/arm_gicv3_cpuif.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

Patch

diff --git a/hw/intc/arm_gicv3_cpuif.c b/hw/intc/arm_gicv3_cpuif.c
index 7fba931450..85fc369e55 100644
--- a/hw/intc/arm_gicv3_cpuif.c
+++ b/hw/intc/arm_gicv3_cpuif.c
@@ -351,7 +351,8 @@  static uint32_t maintenance_interrupt_state(GICv3CPUState *cs)
     /* Scan list registers and fill in the U, NP and EOI bits */
     eoi_maintenance_interrupt_state(cs, &value);
 
-    if (cs->ich_hcr_el2 & (ICH_HCR_EL2_LRENPIE | ICH_HCR_EL2_EOICOUNT_MASK)) {
+    if ((cs->ich_hcr_el2 & ICH_HCR_EL2_LRENPIE) &&
+        (cs->ich_hcr_el2 & ICH_HCR_EL2_EOICOUNT_MASK)) {
         value |= ICH_MISR_EL2_LRENP;
     }