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 <s...@prgmr.com>
Signed-off-by: Andrew Cooper <andrew.coop...@citrix.com>
Tested-by: Chris Brannon <c...@prgmr.com>
---
CC: Jan Beulich <jbeul...@suse.com>
CC: Wei Liu <w...@xen.org>
CC: Roger Pau Monné <roger....@citrix.com>
CC: Jun Nakajima <jun.nakaj...@intel.com>
CC: Kevin Tian <kevin.t...@intel.com>
CC: Juergen Gross <jgr...@suse.com>
This probably wants backporting to all stable trees, even though nested virt
isn't supported, and therefore ought to qualify for 4.13 at this point.
---
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 fdf449bfd1..6696bd6240 100644
--- a/xen/arch/x86/hvm/vmx/vvmx.c
+++ b/xen/arch/x86/hvm/vmx/vvmx.c
@@ -2491,6 +2491,7 @@ 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;
@@ -2501,6 +2502,8 @@ 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;
--
2.11.0
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