From: Joerg Roedel <jroedel@xxxxxxx> 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 recursivly. Handle them by calling the kernels debug exception handler. Signed-off-by: Joerg Roedel <jroedel@xxxxxxx> Link: https://lore.kernel.org/r/20200724160336.5435-64-joro@xxxxxxxxxx --- arch/x86/kernel/sev-es.c | 17 +++++++++++++++++ 1 file changed, 17 insertions(+) diff --git a/arch/x86/kernel/sev-es.c b/arch/x86/kernel/sev-es.c index ee0950f01590..e1f3ebbcc122 100644 --- a/arch/x86/kernel/sev-es.c +++ b/arch/x86/kernel/sev-es.c @@ -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(); /* -- 2.28.0
