From 4601a624f40b2c89e7df2dec1adffb4f4308ba2d Mon Sep 17 00:00:00 2001
From: fanwenjie <fanwj@mail.ustc.edu.cn>
Date: Sun, 1 Jan 2023 23:13:34 +0800
Subject: [PATCH] linux-user: fix bug about incorrect base addresss of idt and
 gdt on i386 and x86_64


Resolves: https://gitlab.com/qemu-project/qemu/-/issues/1405
Signed-off-by: fanwenjie <fanwj@mail.ustc.edu.cn>
---
 linux-user/main.c | 13 +++++++++++++
 1 file changed, 13 insertions(+)


diff --git a/linux-user/main.c b/linux-user/main.c
index a17fed045b..5d673c95b3 100644
--- a/linux-user/main.c
+++ b/linux-user/main.c
@@ -171,6 +171,12 @@ void fork_end(int child)
 
 __thread CPUState *thread_cpu;
 
+#if defined(TARGET_I386) || defined(TARGET_X86_64)
+#include <stdalign.h>
+__thread alignas(TARGET_PAGE_SIZE) static uint64_t gdt_base[TARGET_GDT_ENTRIES];
+__thread alignas(TARGET_PAGE_SIZE) static uint64_t idt_base[TARGET_PAGE_SIZE / sizeof(uint64_t)];
+#endif
+
 bool qemu_cpu_is_self(CPUState *cpu)
 {
     return thread_cpu == cpu;
@@ -235,6 +241,13 @@ CPUArchState *cpu_copy(CPUArchState *env)
     new_cpu->tcg_cflags = cpu->tcg_cflags;
     memcpy(new_env, env, sizeof(CPUArchState));
 
+#if defined(TARGET_I386) || defined(TARGET_X86_64)
+    memcpy(idt_base, (void*)new_env->idt.base, sizeof(uint64_t) * (new_env->idt.limit + 1));
+    memcpy(gdt_base, (void*)new_env->gdt.base, sizeof(uint64_t) * TARGET_GDT_ENTRIES);
+    new_env->idt.base = (target_ulong)idt_base;
+    new_env->gdt.base = (target_ulong)gdt_base;
+#endif
+
     /* Clone all break/watchpoints.
        Note: Once we support ptrace with hw-debug register access, make sure
        BP_CPU break/watchpoints are handled correctly on clone. */
-- 
2.34.1

fanwj@mail.ustc.edu.cn writes:

> From 4601a624f40b2c89e7df2dec1adffb4f4308ba2d Mon Sep 17 00:00:00 2001
> From: fanwenjie <fanwj@mail.ustc.edu.cn>
> Date: Sun, 1 Jan 2023 23:13:34 +0800
> Subject: [PATCH] linux-user: fix bug about incorrect base addresss of idt and
>  gdt on i386 and x86_64
>
> Resolves: https://gitlab.com/qemu-project/qemu/-/issues/1405
> Signed-off-by: fanwenjie <fanwj@mail.ustc.edu.cn>
> ---
>  linux-user/main.c | 13 +++++++++++++
>  1 file changed, 13 insertions(+)
>
> diff --git a/linux-user/main.c b/linux-user/main.c
> index a17fed045b..5d673c95b3 100644
> --- a/linux-user/main.c
> +++ b/linux-user/main.c
> @@ -171,6 +171,12 @@ void fork_end(int child)
>  
>  __thread CPUState *thread_cpu;
>  
> +#if defined(TARGET_I386) || defined(TARGET_X86_64)
> +#include <stdalign.h>
> +__thread alignas(TARGET_PAGE_SIZE) static uint64_t gdt_base[TARGET_GDT_ENTRIES];
> +__thread alignas(TARGET_PAGE_SIZE) static uint64_t idt_base[TARGET_PAGE_SIZE / sizeof(uint64_t)];
> +#endif
> +
>  bool qemu_cpu_is_self(CPUState *cpu)
>  {
>      return thread_cpu == cpu;
> @@ -235,6 +241,13 @@ CPUArchState *cpu_copy(CPUArchState *env)
>      new_cpu->tcg_cflags = cpu->tcg_cflags;
>      memcpy(new_env, env, sizeof(CPUArchState));
>  
> +#if defined(TARGET_I386) || defined(TARGET_X86_64)
> +    memcpy(idt_base, (void*)new_env->idt.base, sizeof(uint64_t) * (new_env->idt.limit + 1));
> +    memcpy(gdt_base, (void*)new_env->gdt.base, sizeof(uint64_t) * TARGET_GDT_ENTRIES);
> +    new_env->idt.base = (target_ulong)idt_base;
> +    new_env->gdt.base = (target_ulong)gdt_base;
> +#endif
> +

This is the wrong place to copy target specific bits of code. I think
this belongs with cpu_clone_regs_child and the gdt/idt structures in
linux-user/i386/cpu_loop.c I think.

>      /* Clone all break/watchpoints.
>         Note: Once we support ptrace with hw-debug register access, make sure
>         BP_CPU break/watchpoints are handled correctly on clone. */


-- 
Alex Bennée
Virtualisation Tech Lead @ Linaro

The Patch has some problem, Please RECALL it!


-----原始邮件-----
发件人:fanwj@mail.ustc.edu.cn
发送时间:2023-01-01 23:57:06 (星期日)
收件人: qemu-devel@nongnu.org
抄送: qemu-devel@nongnu.org
主题: [PATCH] linux-user: fix bug about incorrect base addresss of idt and gdt on i386 and x86_64


From 4601a624f40b2c89e7df2dec1adffb4f4308ba2d Mon Sep 17 00:00:00 2001
From: fanwenjie <fanwj@mail.ustc.edu.cn>
Date: Sun, 1 Jan 2023 23:13:34 +0800
Subject: [PATCH] linux-user: fix bug about incorrect base addresss of idt and
 gdt on i386 and x86_64


Resolves: https://gitlab.com/qemu-project/qemu/-/issues/1405
Signed-off-by: fanwenjie <fanwj@mail.ustc.edu.cn>
---
 linux-user/main.c | 13 +++++++++++++
 1 file changed, 13 insertions(+)


diff --git a/linux-user/main.c b/linux-user/main.c
index a17fed045b..5d673c95b3 100644
--- a/linux-user/main.c
+++ b/linux-user/main.c
@@ -171,6 +171,12 @@ void fork_end(int child)
 
 __thread CPUState *thread_cpu;
 
+#if defined(TARGET_I386) || defined(TARGET_X86_64)
+#include <stdalign.h>
+__thread alignas(TARGET_PAGE_SIZE) static uint64_t gdt_base[TARGET_GDT_ENTRIES];
+__thread alignas(TARGET_PAGE_SIZE) static uint64_t idt_base[TARGET_PAGE_SIZE / sizeof(uint64_t)];
+#endif
+
 bool qemu_cpu_is_self(CPUState *cpu)
 {
     return thread_cpu == cpu;
@@ -235,6 +241,13 @@ CPUArchState *cpu_copy(CPUArchState *env)
     new_cpu->tcg_cflags = cpu->tcg_cflags;
     memcpy(new_env, env, sizeof(CPUArchState));
 
+#if defined(TARGET_I386) || defined(TARGET_X86_64)
+    memcpy(idt_base, (void*)new_env->idt.base, sizeof(uint64_t) * (new_env->idt.limit + 1));
+    memcpy(gdt_base, (void*)new_env->gdt.base, sizeof(uint64_t) * TARGET_GDT_ENTRIES);
+    new_env->idt.base = (target_ulong)idt_base;
+    new_env->gdt.base = (target_ulong)gdt_base;
+#endif
+
     /* Clone all break/watchpoints.
        Note: Once we support ptrace with hw-debug register access, make sure
        BP_CPU break/watchpoints are handled correctly on clone. */
-- 
2.34.1