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 <[email protected]>
Reviewed-by: Peter Maydell <[email protected]>
Message-id: 20211207094427[email protected]
Signed-off-by: Peter Maydell <[email protected]>

diff --git a/hw/intc/arm_gicv3_cpuif.c b/hw/intc/arm_gicv3_cpuif.c
index 7fba93145085c75814bec44387ccbf55049bec62..85fc369e55019bc332af7a974f5b60ebfcf33d59 100644 (file)
--- 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;
     }