[Qemu-devel] [PATCH 2/3] target-arm: A64: fix TLB flush instructions

["Alex Bennée" <alex.bennee@linaro.org>]

According to the ARM ARM we weren't correctly flushing the TLB entries
where bits 63:56 didn't match bit 55 of the virtual address. This
exposed a problem when we switched QEMU's internal TARGET_PAGE_BITS to
12 for aarch64.

Signed-off-by: Alex Bennée <alex.bennee@linaro.org>

diff --git a/target-arm/helper.c b/target-arm/helper.c
index aa5d267..b0d0411 100644
--- a/target-arm/helper.c
+++ b/target-arm/helper.c
@@ -1766,12 +1766,19 @@ static CPAccessResult aa64_cacheop_access(CPUARMState *env,
     return CP_ACCESS_OK;
 }
 
+/* See: D4.7.2 TLB maintenance requirements and the TLB maintenance instructions
+ * Page D4-1736 (DDI0487A.b) "For TLB maintenance instructions that
+ * take an address, the maintenance of VA[63:56] is interpreted as
+ * being the same as the maintenance of VA[55]"
+ */
+
 static void tlbi_aa64_va_write(CPUARMState *env, const ARMCPRegInfo *ri,
                                uint64_t value)
 {
     /* Invalidate by VA (AArch64 version) */
     ARMCPU *cpu = arm_env_get_cpu(env);
-    uint64_t pageaddr = value << 12;
+    uint64_t pageaddr = sextract64(value << 12, 0, 56);
+
     tlb_flush_page(CPU(cpu), pageaddr);
 }
 
@@ -1780,7 +1787,8 @@ static void tlbi_aa64_vaa_write(CPUARMState *env, const ARMCPRegInfo *ri,
 {
     /* Invalidate by VA, all ASIDs (AArch64 version) */
     ARMCPU *cpu = arm_env_get_cpu(env);
-    uint64_t pageaddr = value << 12;
+    uint64_t pageaddr = sextract64(value << 12, 0, 56);
+
     tlb_flush_page(CPU(cpu), pageaddr);
 }
 
-- 
2.0.2