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| author | Lai Jiangshan <jiangshan.ljs@antgroup.com> | 2022-05-03 06:21:06 +0300 |
|---|---|---|
| committer | Borislav Petkov <bp@suse.de> | 2022-05-03 13:21:35 +0300 |
| commit | 64cbd0acb58203fb769ed2f4eab526d43e243847 (patch) | |
| tree | 16c3900676939b369891d54193e08d29bcbcf9ce | |
| parent | c64cc2802a784ecfd25d39945e57e7a147854a5b (diff) | |
| download | linux-64cbd0acb58203fb769ed2f4eab526d43e243847.tar.xz | |
x86/entry: Don't call error_entry() for XENPV
XENPV guests enter already on the task stack and they can't fault for
native_iret() nor native_load_gs_index() since they use their own pvop
for IRET and load_gs_index(). A CR3 switch is not needed either.
So there is no reason to call error_entry() in XENPV.
[ bp: Massage commit message. ]
Signed-off-by: Lai Jiangshan <jiangshan.ljs@antgroup.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Juergen Gross <jgross@suse.com>
Link: https://lore.kernel.org/r/20220503032107.680190-6-jiangshanlai@gmail.com
| -rw-r--r-- | arch/x86/entry/entry_64.S | 13 |
1 files changed, 11 insertions, 2 deletions
diff --git a/arch/x86/entry/entry_64.S b/arch/x86/entry/entry_64.S index ab6ab6d3dab5..062aa9d95961 100644 --- a/arch/x86/entry/entry_64.S +++ b/arch/x86/entry/entry_64.S @@ -336,8 +336,17 @@ SYM_CODE_END(push_and_clear_regs) call push_and_clear_regs UNWIND_HINT_REGS - call error_entry - movq %rax, %rsp /* switch to the task stack if from userspace */ + /* + * Call error_entry() and switch to the task stack if from userspace. + * + * When in XENPV, it is already in the task stack, and it can't fault + * for native_iret() nor native_load_gs_index() since XENPV uses its + * own pvops for IRET and load_gs_index(). And it doesn't need to + * switch the CR3. So it can skip invoking error_entry(). + */ + ALTERNATIVE "call error_entry; movq %rax, %rsp", \ + "", X86_FEATURE_XENPV + ENCODE_FRAME_POINTER UNWIND_HINT_REGS |