diff options
| author |   Lai Jiangshan <jiangshan.ljs@antgroup.com> | 2022-03-16 12:16:12 +0800 |
|---|---|---|
| committer |   Borislav Petkov <bp@suse.de> | 2022-05-18 20:36:03 +0200 |
| commit | c42b145181aafd59ed31ccd879493389e3ea5a08 (patch) | |
| tree | 9c3304c863529c380066dbc055fb69a139b0247d /arch/x86/entry/entry_64.S | |
| parent | x86/sev: Remove duplicated assignment to variable info (diff) | |
| download | wireguard-linux-c42b145181aafd59ed31ccd879493389e3ea5a08.tar.xz wireguard-linux-c42b145181aafd59ed31ccd879493389e3ea5a08.zip | |
x86/sev: Annotate stack change in the #VC handler
In idtentry_vc(), vc_switch_off_ist() determines a safe stack to
switch to, off of the IST stack. Annotate the new stack switch with
ENCODE_FRAME_POINTER in case UNWINDER_FRAME_POINTER is used.
A stack walk before looks like this:
CPU: 0 PID: 0 Comm: swapper Not tainted 5.18.0-rc7+ #2
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 0.0.0 02/06/2015
Call Trace:
<TASK>
dump_stack_lvl
dump_stack
kernel_exc_vmm_communication
asm_exc_vmm_communication
? native_read_msr
? __x2apic_disable.part.0
? x2apic_setup
? cpu_init
? trap_init
? start_kernel
? x86_64_start_reservations
? x86_64_start_kernel
? secondary_startup_64_no_verify
</TASK>
and with the fix, the stack dump is exact:
CPU: 0 PID: 0 Comm: swapper Not tainted 5.18.0-rc7+ #3
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 0.0.0 02/06/2015
Call Trace:
<TASK>
dump_stack_lvl
dump_stack
kernel_exc_vmm_communication
asm_exc_vmm_communication
RIP: 0010:native_read_msr
Code: ...
< snipped regs >
? __x2apic_disable.part.0
x2apic_setup
cpu_init
trap_init
start_kernel
x86_64_start_reservations
x86_64_start_kernel
secondary_startup_64_no_verify
</TASK>
[ bp: Test in a SEV-ES guest and rewrite the commit message to
explain what exactly this does. ]
Fixes: a13644f3a53d ("x86/entry/64: Add entry code for #VC handler")
Signed-off-by: Lai Jiangshan <jiangshan.ljs@antgroup.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Acked-by: Josh Poimboeuf <jpoimboe@redhat.com>
Link: https://lore.kernel.org/r/20220316041612.71357-1-jiangshanlai@gmail.com
Diffstat (limited to 'arch/x86/entry/entry_64.S')
| -rw-r--r-- | arch/x86/entry/entry_64.S | 1 |
1 files changed, 1 insertions, 0 deletions
diff --git a/arch/x86/entry/entry_64.S b/arch/x86/entry/entry_64.S index 4faac48ebec5..f7bd8001bf07 100644 --- a/arch/x86/entry/entry_64.S +++ b/arch/x86/entry/entry_64.S @@ -505,6 +505,7 @@ SYM_CODE_START(\asmsym) call vc_switch_off_ist movq %rax, %rsp /* Switch to new stack */ + ENCODE_FRAME_POINTER UNWIND_HINT_REGS /* Update pt_regs */ |