From 58668f12a6e65cd6a384abad001ff5dae69b161f Mon Sep 17 00:00:00 2001 From: Andrew Cooper Date: Mon, 25 Nov 2019 15:50:44 +0100 Subject: [PATCH] x86/vvmx: Fix the use of RDTSCP when it is intercepted at L0 Linux has started using RDTSCP as of v5.1. This has highlighted a bug in Xen, where virtual vmexit simply gives up. (XEN) d1v1 Unhandled nested vmexit: reason 51 (XEN) domain_crash called from vvmx.c:2671 (XEN) Domain 1 (vcpu#1) crashed on cpu#2: Handle RDTSCP in the virtual vmexit hander in the same was as RDTSC intercepts. Reported-by: Sarah Newman Signed-off-by: Andrew Cooper Tested-by: Chris Brannon Reviewed-by: Wei Liu master commit: 9257c218e56e9902b78662e5852d69329b9cc204 master date: 2019-10-23 16:43:48 +0100 --- xen/arch/x86/hvm/vmx/vvmx.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/xen/arch/x86/hvm/vmx/vvmx.c b/xen/arch/x86/hvm/vmx/vvmx.c index f03660b51e..02c8c0fd50 100644 --- a/xen/arch/x86/hvm/vmx/vvmx.c +++ b/xen/arch/x86/hvm/vmx/vvmx.c @@ -2487,6 +2487,7 @@ int nvmx_n2_vmexit_handler(struct cpu_user_regs *regs, nvcpu->nv_vmexit_pending = 1; break; case EXIT_REASON_RDTSC: + case EXIT_REASON_RDTSCP: ctrl = __n2_exec_control(v); if ( ctrl & CPU_BASED_RDTSC_EXITING ) nvcpu->nv_vmexit_pending = 1; @@ -2497,6 +2498,8 @@ int nvmx_n2_vmexit_handler(struct cpu_user_regs *regs, * avoiding changing guest_tsc and messing up timekeeping in L1 */ msr_split(regs, hvm_get_guest_tsc(v) + get_vvmcs(v, TSC_OFFSET)); + if ( exit_reason == EXIT_REASON_RDTSCP ) + regs->rcx = v->arch.msrs->tsc_aux; update_guest_eip(); return 1; -- 2.39.5