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[PULL 11/13] target/i386/tcg: save current task state before loading new
From: |
Paolo Bonzini |
Subject: |
[PULL 11/13] target/i386/tcg: save current task state before loading new one |
Date: |
Sun, 14 Jul 2024 13:10:41 +0200 |
This is how the steps are ordered in the manual. EFLAGS.NT is
overwritten after the fact in the saved image.
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
---
target/i386/tcg/seg_helper.c | 85 +++++++++++++++++++-----------------
1 file changed, 45 insertions(+), 40 deletions(-)
diff --git a/target/i386/tcg/seg_helper.c b/target/i386/tcg/seg_helper.c
index fea08a2ba0f..c0641a79c70 100644
--- a/target/i386/tcg/seg_helper.c
+++ b/target/i386/tcg/seg_helper.c
@@ -389,6 +389,42 @@ static int switch_tss_ra(CPUX86State *env, int
tss_selector,
access_prepare_mmu(&new, env, tss_base, tss_limit,
MMU_DATA_LOAD, mmu_index, retaddr);
+ /* save the current state in the old TSS */
+ old_eflags = cpu_compute_eflags(env);
+ if (old_type & 8) {
+ /* 32 bit */
+ access_stl(&old, env->tr.base + 0x20, next_eip);
+ access_stl(&old, env->tr.base + 0x24, old_eflags);
+ access_stl(&old, env->tr.base + (0x28 + 0 * 4), env->regs[R_EAX]);
+ access_stl(&old, env->tr.base + (0x28 + 1 * 4), env->regs[R_ECX]);
+ access_stl(&old, env->tr.base + (0x28 + 2 * 4), env->regs[R_EDX]);
+ access_stl(&old, env->tr.base + (0x28 + 3 * 4), env->regs[R_EBX]);
+ access_stl(&old, env->tr.base + (0x28 + 4 * 4), env->regs[R_ESP]);
+ access_stl(&old, env->tr.base + (0x28 + 5 * 4), env->regs[R_EBP]);
+ access_stl(&old, env->tr.base + (0x28 + 6 * 4), env->regs[R_ESI]);
+ access_stl(&old, env->tr.base + (0x28 + 7 * 4), env->regs[R_EDI]);
+ for (i = 0; i < 6; i++) {
+ access_stw(&old, env->tr.base + (0x48 + i * 4),
+ env->segs[i].selector);
+ }
+ } else {
+ /* 16 bit */
+ access_stw(&old, env->tr.base + 0x0e, next_eip);
+ access_stw(&old, env->tr.base + 0x10, old_eflags);
+ access_stw(&old, env->tr.base + (0x12 + 0 * 2), env->regs[R_EAX]);
+ access_stw(&old, env->tr.base + (0x12 + 1 * 2), env->regs[R_ECX]);
+ access_stw(&old, env->tr.base + (0x12 + 2 * 2), env->regs[R_EDX]);
+ access_stw(&old, env->tr.base + (0x12 + 3 * 2), env->regs[R_EBX]);
+ access_stw(&old, env->tr.base + (0x12 + 4 * 2), env->regs[R_ESP]);
+ access_stw(&old, env->tr.base + (0x12 + 5 * 2), env->regs[R_EBP]);
+ access_stw(&old, env->tr.base + (0x12 + 6 * 2), env->regs[R_ESI]);
+ access_stw(&old, env->tr.base + (0x12 + 7 * 2), env->regs[R_EDI]);
+ for (i = 0; i < 4; i++) {
+ access_stw(&old, env->tr.base + (0x22 + i * 2),
+ env->segs[i].selector);
+ }
+ }
+
/* read all the registers from the new TSS */
if (type & 8) {
/* 32 bit */
@@ -428,49 +464,16 @@ static int switch_tss_ra(CPUX86State *env, int
tss_selector,
if (source == SWITCH_TSS_JMP || source == SWITCH_TSS_IRET) {
tss_set_busy(env, env->tr.selector, 0, retaddr);
}
- old_eflags = cpu_compute_eflags(env);
+
if (source == SWITCH_TSS_IRET) {
old_eflags &= ~NT_MASK;
+ if (old_type & 8) {
+ access_stl(&old, env->tr.base + 0x24, old_eflags);
+ } else {
+ access_stw(&old, env->tr.base + 0x10, old_eflags);
+ }
}
- /* save the current state in the old TSS */
- if (old_type & 8) {
- /* 32 bit */
- access_stl(&old, env->tr.base + 0x20, next_eip);
- access_stl(&old, env->tr.base + 0x24, old_eflags);
- access_stl(&old, env->tr.base + (0x28 + 0 * 4), env->regs[R_EAX]);
- access_stl(&old, env->tr.base + (0x28 + 1 * 4), env->regs[R_ECX]);
- access_stl(&old, env->tr.base + (0x28 + 2 * 4), env->regs[R_EDX]);
- access_stl(&old, env->tr.base + (0x28 + 3 * 4), env->regs[R_EBX]);
- access_stl(&old, env->tr.base + (0x28 + 4 * 4), env->regs[R_ESP]);
- access_stl(&old, env->tr.base + (0x28 + 5 * 4), env->regs[R_EBP]);
- access_stl(&old, env->tr.base + (0x28 + 6 * 4), env->regs[R_ESI]);
- access_stl(&old, env->tr.base + (0x28 + 7 * 4), env->regs[R_EDI]);
- for (i = 0; i < 6; i++) {
- access_stw(&old, env->tr.base + (0x48 + i * 4),
- env->segs[i].selector);
- }
- } else {
- /* 16 bit */
- access_stw(&old, env->tr.base + 0x0e, next_eip);
- access_stw(&old, env->tr.base + 0x10, old_eflags);
- access_stw(&old, env->tr.base + (0x12 + 0 * 2), env->regs[R_EAX]);
- access_stw(&old, env->tr.base + (0x12 + 1 * 2), env->regs[R_ECX]);
- access_stw(&old, env->tr.base + (0x12 + 2 * 2), env->regs[R_EDX]);
- access_stw(&old, env->tr.base + (0x12 + 3 * 2), env->regs[R_EBX]);
- access_stw(&old, env->tr.base + (0x12 + 4 * 2), env->regs[R_ESP]);
- access_stw(&old, env->tr.base + (0x12 + 5 * 2), env->regs[R_EBP]);
- access_stw(&old, env->tr.base + (0x12 + 6 * 2), env->regs[R_ESI]);
- access_stw(&old, env->tr.base + (0x12 + 7 * 2), env->regs[R_EDI]);
- for (i = 0; i < 4; i++) {
- access_stw(&old, env->tr.base + (0x22 + i * 2),
- env->segs[i].selector);
- }
- }
-
- /* now if an exception occurs, it will occurs in the next task
- context */
-
if (source == SWITCH_TSS_CALL) {
/*
* Thanks to the probe_access above, we know the first two
@@ -486,7 +489,9 @@ static int switch_tss_ra(CPUX86State *env, int tss_selector,
}
/* set the new CPU state */
- /* from this point, any exception which occurs can give problems */
+
+ /* now if an exception occurs, it will occur in the next task context */
+
env->cr[0] |= CR0_TS_MASK;
env->hflags |= HF_TS_MASK;
env->tr.selector = tss_selector;
--
2.45.2
- [PULL 03/13] target/i386/tcg: Allow IRET from user mode to user mode with SMAP, (continued)
- [PULL 03/13] target/i386/tcg: Allow IRET from user mode to user mode with SMAP, Paolo Bonzini, 2024/07/14
- [PULL 01/13] target/i386/tcg: fix POP to memory in long mode, Paolo Bonzini, 2024/07/14
- [PULL 02/13] target/i386/tcg: Remove SEG_ADDL, Paolo Bonzini, 2024/07/14
- [PULL 04/13] target/i386/tcg: use PUSHL/PUSHW for error code, Paolo Bonzini, 2024/07/14
- [PULL 05/13] target/i386/tcg: Reorg push/pop within seg_helper.c, Paolo Bonzini, 2024/07/14
- [PULL 06/13] target/i386/tcg: Introduce x86_mmu_index_{kernel_,}pl, Paolo Bonzini, 2024/07/14
- [PULL 07/13] target/i386/tcg: Compute MMU index once, Paolo Bonzini, 2024/07/14
- [PULL 08/13] target/i386/tcg: Use DPL-level accesses for interrupts and call gates, Paolo Bonzini, 2024/07/14
- [PULL 09/13] target/i386/tcg: check for correct busy state before switching to a new task, Paolo Bonzini, 2024/07/14
- [PULL 10/13] target/i386/tcg: use X86Access for TSS access, Paolo Bonzini, 2024/07/14
- [PULL 11/13] target/i386/tcg: save current task state before loading new one,
Paolo Bonzini <=
- [PULL 13/13] Revert "qemu-char: do not operate on sources from finalize callbacks", Paolo Bonzini, 2024/07/14
- [PULL 12/13] i386/sev: Don't allow automatic fallback to legacy KVM_SEV*_INIT, Paolo Bonzini, 2024/07/14
- Re: [PULL 00/13] target/i386 changes for 2024-07-12, Richard Henderson, 2024/07/14