diff options
| author | Richard Henderson <richard.henderson@linaro.org> | 2024-08-19 17:39:55 +1000 |
|---|---|---|
| committer | Richard Henderson <richard.henderson@linaro.org> | 2024-08-21 09:11:26 +1000 |
| commit | ded1db48c9f9b35f6d9569e53503e2b345f6d44e (patch) | |
| tree | 83fc56b4e8bd61b1e69492a9c5ecdbd946826e83 | |
| parent | 83a3a20e59fa4b1add714bb4062af0d144b67ab7 (diff) | |
target/i386: Fix tss access size in switch_tss_ra
The two limit_max variables represent size - 1, just like the
encoding in the GDT, thus the 'old' access was off by one.
Access the minimal size of the new tss: the complete tss contains
the iopb, which may be a larger block than the access api expects,
and irrelevant because the iopb is not accessed during the
switch itself.
Fixes: 8b131065080a ("target/i386/tcg: use X86Access for TSS access")
Resolves: https://gitlab.com/qemu-project/qemu/-/issues/2511
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Message-Id: <20240819074052.207783-1-richard.henderson@linaro.org>
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Pierrick Bouvier <pierrick.bouvier@linaro.org>
| -rw-r--r-- | target/i386/tcg/seg_helper.c | 5 |
1 files changed, 3 insertions, 2 deletions
diff --git a/target/i386/tcg/seg_helper.c b/target/i386/tcg/seg_helper.c index bab552cd53..3b8fd827e1 100644 --- a/target/i386/tcg/seg_helper.c +++ b/target/i386/tcg/seg_helper.c @@ -378,7 +378,7 @@ static int switch_tss_ra(CPUX86State *env, int tss_selector, /* X86Access avoids memory exceptions during the task switch */ mmu_index = cpu_mmu_index_kernel(env); - access_prepare_mmu(&old, env, env->tr.base, old_tss_limit_max, + access_prepare_mmu(&old, env, env->tr.base, old_tss_limit_max + 1, MMU_DATA_STORE, mmu_index, retaddr); if (source == SWITCH_TSS_CALL) { @@ -386,7 +386,8 @@ static int switch_tss_ra(CPUX86State *env, int tss_selector, probe_access(env, tss_base, 2, MMU_DATA_STORE, mmu_index, retaddr); } - access_prepare_mmu(&new, env, tss_base, tss_limit, + /* While true tss_limit may be larger, we don't access the iopb here. */ + access_prepare_mmu(&new, env, tss_base, tss_limit_max + 1, MMU_DATA_LOAD, mmu_index, retaddr); /* save the current state in the old TSS */ |