From: Bibo Mao <maobibo@loongson.cn>
Date: Mon, 14 Jul 2025 01:54:46 +0000 (+0800)
Subject: target/loongarch: Fix valid virtual address checking
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=caab7ac83507e3e9a5fe2f37be5cfa759e766ba2;p=thirdparty%2Fqemu.git

target/loongarch: Fix valid virtual address checking

On LoongArch64 system, the high 32 bit of 64 bit virtual address should be
0x00000[0-7]yyy or 0xffff8yyy. The bit from 47 to 63 should be all 0 or
all 1.

Function get_physical_address() only checks bit 48 to 63, there will be
problem with the following test case. On physical machine, there is bus
error report and program exits abnormally. However on qemu TCG system
emulation mode, the program runs normally. The virtual address
0xffff000000000000ULL + addr and addr are treated the same on TLB entry
checking. This patch fixes this issue.

void main()
{
        void *addr, *addr1;
        int val;

        addr = malloc(100);
        *(int *)addr = 1;
        addr1 = 0xffff000000000000ULL + addr;
        val = *(int *)addr1;
        printf("val %d \n", val);
}

Cc: qemu-stable@nongnu.org
Signed-off-by: Bibo Mao <maobibo@loongson.cn>
Acked-by: Song Gao <gaosong@loongson.cn>
Reviewed-by: Song Gao <gaosong@loongson.cn>
Message-ID: <20250714015446.746163-1-maobibo@loongson.cn>
Signed-off-by: Song Gao <gaosong@loongson.cn>
---

diff --git a/target/loongarch/cpu_helper.c b/target/loongarch/cpu_helper.c
index e172b11ce1..b5f732f15b 100644
--- a/target/loongarch/cpu_helper.c
+++ b/target/loongarch/cpu_helper.c
@@ -196,8 +196,8 @@ int get_physical_address(CPULoongArchState *env, hwaddr *physical,
     }
 
     /* Check valid extension */
-    addr_high = sextract64(address, TARGET_VIRT_ADDR_SPACE_BITS, 16);
-    if (!(addr_high == 0 || addr_high == -1)) {
+    addr_high = (int64_t)address >> (TARGET_VIRT_ADDR_SPACE_BITS - 1);
+    if (!(addr_high == 0 || addr_high == -1ULL)) {
         return TLBRET_BADADDR;
     }