On Wed, 20 Mar 2024 at 02:40, Song Gao <gaos...@loongson.cn> wrote:
>
> From: Xianglai Li <lixiang...@loongson.cn>
>
> When we use qemu tcg simulation, the page size of bios is 4KB.
> When using the level 2 super huge page (page size is 1G) to create the page
> table,
> it is found that the content of the corresponding address space is abnormal,
> resulting in the bios can not start the operating system and graphical
> interface normally.
>
> The lddir and ldpte instruction emulation has
> a problem with the use of super huge page processing above level 2.
> The page size is not correctly calculated,
> resulting in the wrong page size of the table entry found by tlb.
>
> Signed-off-by: Xianglai Li <lixiang...@loongson.cn>
> Reviewed-by: Richard Henderson <richard.hender...@linaro.org>
> Signed-off-by: Song Gao <gaos...@loongson.cn>
> Message-Id: <20240318070332.1273939-1-lixiang...@loongson.cn>
Hi; Coverity points out an issue with this patch (Coverity
CID 1547717):
> @@ -485,7 +513,25 @@ target_ulong helper_lddir(CPULoongArchState *env,
> target_ulong base,
> target_ulong badvaddr, index, phys, ret;
> int shift;
> uint64_t dir_base, dir_width;
> - bool huge = (base >> LOONGARCH_PAGE_HUGE_SHIFT) & 0x1;
> +
> + if (unlikely((level == 0) || (level > 4))) {
> + qemu_log_mask(LOG_GUEST_ERROR,
> + "Attepted LDDIR with level %"PRId64"\n", level);
> + return base;
> + }
> +
> + if (FIELD_EX64(base, TLBENTRY, HUGE)) {
> + if (unlikely(level == 4)) {
> + qemu_log_mask(LOG_GUEST_ERROR,
> + "Attempted use of level 4 huge page\n");
Here we log level == 4 as being a guest error, but there is no
early "return <something>" the way the previous error-exit
codepath did above...
> + }
> +
> + if (FIELD_EX64(base, TLBENTRY, LEVEL)) {
> + return base;
> + } else {
> + return FIELD_DP64(base, TLBENTRY, LEVEL, level);
...so Coverity complains that here we will try to put that value 4
into a field in the TLBENTRY that is only 2 bits wide.
> + }
> + }
Should the level == 4 if() do a "return base" like the
error cases for level == 0 or > 4 ?
thanks
-- PMM
