hw/intc/arm_gicv3_cpuif: Fix EOIR write access check logic

In icc_eoir_write() we assume that we can identify the group of the
IRQ being completed based purely on which register is being written
to and the current CPU state, and that "CPU state matches group
indicated by register" is the only necessary access check.

This isn't correct: if the CPU is not in Secure state then EOIR1 will
only complete Group 1 NS IRQs, but if the CPU is in EL3 it can
complete both Group 1 S and Group 1 NS IRQs.  (The pseudocode
ICC_EOIR1_EL1 makes this clear.) We were also missing the logic to
prevent EOIR0 writes completing G0 IRQs when they should not.

Rearrange the logic to first identify the group of the current
highest priority interrupt and then look at whether we should
complete it or ignore the access based on which register was accessed
and the state of the CPU.  The resulting behavioural change is:
 * EL3 can now complete G1NS interrupts
 * G0 interrupt completion is now ignored if the GIC
   and the CPU have the security extension enabled and
   the CPU is not secure

Reported-by: Chan Kim <ckim@etri.re.kr>
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-id: 20210510150016.24910-1-peter.maydell@linaro.org

diff --git a/hw/intc/arm_gicv3_cpuif.c b/hw/intc/arm_gicv3_cpuif.c
index 43ef1d7a8405b4bc8b87654885a066d3cff2c754..81f94c7f4adee0d3ca7218d25756ae3889cf6d2c 100644 (file)
--- a/hw/intc/arm_gicv3_cpuif.c
+++ b/hw/intc/arm_gicv3_cpuif.c
@@ -1307,27 +1307,16 @@ static void icc_eoir_write(CPUARMState *env, const ARMCPRegInfo *ri,
     GICv3CPUState *cs = icc_cs_from_env(env);
     int irq = value & 0xffffff;
     int grp;
+    bool is_eoir0 = ri->crm == 8;
 
-    if (icv_access(env, ri->crm == 8 ? HCR_FMO : HCR_IMO)) {
+    if (icv_access(env, is_eoir0 ? HCR_FMO : HCR_IMO)) {
         icv_eoir_write(env, ri, value);
         return;
     }
 
-    trace_gicv3_icc_eoir_write(ri->crm == 8 ? 0 : 1,
+    trace_gicv3_icc_eoir_write(is_eoir0 ? 0 : 1,
                                gicv3_redist_affid(cs), value);
 
-    if (ri->crm == 8) {
-        /* EOIR0 */
-        grp = GICV3_G0;
-    } else {
-        /* EOIR1 */
-        if (arm_is_secure(env)) {
-            grp = GICV3_G1;
-        } else {
-            grp = GICV3_G1NS;
-        }
-    }
-
     if (irq >= cs->gic->num_irq) {
         /* This handles two cases:
          * 1. If software writes the ID of a spurious interrupt [ie 1020-1023]
@@ -1340,8 +1329,35 @@ static void icc_eoir_write(CPUARMState *env, const ARMCPRegInfo *ri,
         return;
     }
 
-    if (icc_highest_active_group(cs) != grp) {
-        return;
+    grp = icc_highest_active_group(cs);
+    switch (grp) {
+    case GICV3_G0:
+        if (!is_eoir0) {
+            return;
+        }
+        if (!(cs->gic->gicd_ctlr & GICD_CTLR_DS)
+            && arm_feature(env, ARM_FEATURE_EL3) && !arm_is_secure(env)) {
+            return;
+        }
+        break;
+    case GICV3_G1:
+        if (is_eoir0) {
+            return;
+        }
+        if (!arm_is_secure(env)) {
+            return;
+        }
+        break;
+    case GICV3_G1NS:
+        if (is_eoir0) {
+            return;
+        }
+        if (!arm_is_el3_or_mon(env) && arm_is_secure(env)) {
+            return;
+        }
+        break;
+    default:
+        g_assert_not_reached();
     }
 
     icc_drop_prio(cs, grp);