x86/sev: Mark the code returning to user space as syscall gap

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When returning to user space, %rsp is user-controlled value.

If it is a SNP-guest and the hypervisor decides to mess with the
code-page for this path while a CPU is executing it, a potential #VC
could hit in the syscall return path and mislead the #VC handler.

So make ip_within_syscall_gap() return true in this case.

Signed-off-by: Lai Jiangshan <jiangshan.ljs@antgroup.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Acked-by: Joerg Roedel <jroedel@suse.de>
Link: https://lore.kernel.org/r/20220412124909.10467-1-jiangshanlai@gmail.com

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Lai Jiangshan 2022-04-12 20:49:08 +08:00 • committed by Borislav Petkov

parent c42b145181

commit 47f33de4aa

4 changed files with 12 additions and 0 deletions

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2

arch/x86/entry/entry_64.S

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arch/x86/entry/entry_64_compat.S

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arch/x86/include/asm/proto.h

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arch/x86/include/asm/ptrace.h

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