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x86/sev-es: Handle #DB Events

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Handle #VC exceptions caused by #DB exceptions in the guest. Those
must be handled outside of instrumentation_begin()/end() so that the
handler will not be raised recursively.

Handle them by calling the kernel's debug exception handler.

Signed-off-by: Joerg Roedel <jroedel@suse.de>
Signed-off-by: Borislav Petkov <bp@suse.de>
Link: https://lkml.kernel.org/r/20200907131613.12703-62-joro@8bytes.org
This commit is contained in:
Joerg Roedel 2020-09-07 15:16:02 +02:00 committed by Borislav Petkov
parent a2d0171a9c
commit cb1ad3ecea
1 changed files with 17 additions and 0 deletions
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17
arch/x86/kernel/sev-es.c
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@ -922,6 +922,14 @@ static enum es_result vc_handle_trap_ac(struct ghcb *ghcb,
return ES_EXCEPTION;
}
static __always_inline void vc_handle_trap_db(struct pt_regs *regs)
{
if (user_mode(regs))
noist_exc_debug(regs);
else
exc_debug(regs);
}
static enum es_result vc_handle_exitcode(struct es_em_ctxt *ctxt,
struct ghcb *ghcb,
unsigned long exit_code)
@ -1033,6 +1041,15 @@ DEFINE_IDTENTRY_VC_SAFE_STACK(exc_vmm_communication)
struct ghcb *ghcb;
lockdep_assert_irqs_disabled();
/*
* Handle #DB before calling into !noinstr code to avoid recursive #DB.
*/
if (error_code == SVM_EXIT_EXCP_BASE + X86_TRAP_DB) {
vc_handle_trap_db(regs);
return;
}
instrumentation_begin();
/*