From 1495b4ff9b4af2b9c0f12cdb6491082cecf34f86 Mon Sep 17 00:00:00 2001 From: Andrew Cooper Date: Fri, 1 Feb 2019 14:48:48 +0000 Subject: [PATCH] x86/svm: Fix handling of ICEBP intercepts c/s 9338a37d "x86/svm: implement debug events" added support for introspecting ICEBP debug exceptions, but didn't account for the fact that svm_get_insn_len() (previously __get_instruction_length) can fail and may already have raised #GP with the guest. If svm_get_insn_len() fails, return back to guest context rather than continuing and mistaking a trap-style VMExit for a fault-style one. Spotted by Coverity. Signed-off-by: Andrew Cooper Reviewed-by: Razvan Cojocaru Acked-by: Brian Woods --- xen/arch/x86/hvm/svm/svm.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/xen/arch/x86/hvm/svm/svm.c b/xen/arch/x86/hvm/svm/svm.c index 506258abdc..0beb31bbe9 100644 --- a/xen/arch/x86/hvm/svm/svm.c +++ b/xen/arch/x86/hvm/svm/svm.c @@ -2760,6 +2760,9 @@ void svm_vmexit_handler(struct cpu_user_regs *regs) { trap_type = X86_EVENTTYPE_PRI_SW_EXCEPTION; inst_len = svm_get_insn_len(v, INSTR_ICEBP); + + if ( !inst_len ) + break; } rc = hvm_monitor_debug(regs->rip, -- 2.30.2