From: Chris Brannon <cmb@prgmr.com>
To: Andrew Cooper <andrew.cooper3@citrix.com>
Cc: Sarah Newman <srn@prgmr.com>, Jan Beulich <JBeulich@suse.com>,
"xen-devel@lists.xen.org" <xen-devel@lists.xen.org>
Subject: Re: [Xen-devel] Crash with nested HVM and Linux v5.1+
Date: Wed, 02 Oct 2019 13:55:44 -0700 [thread overview]
Message-ID: <87pnje50kv.fsf@cmbmachine.messageid.invalid> (raw)
In-Reply-To: <e05593f6-f223-2c7d-d607-ea76c9204f17@citrix.com> (Andrew Cooper's message of "Wed, 2 Oct 2019 18:41:32 +0100")
Andrew Cooper <andrew.cooper3@citrix.com> writes:
> (XEN) traps.c:1576: GPF (0000): ffff82d08031a80f [vmx.c#vmx_msr_read_intercept+0x387/0x3fd] -> ffff82d08037c9f2
> (XEN) traps.c:1576: GPF (0000): ffff82d08031a80f [vmx.c#vmx_msr_read_intercept+0x387/0x3fd] -> ffff82d08037c9f2
> (d2) xs_write(/vm/95f11fc0-b9e7-47ff-8523-bacab35b96b6/rtc/timeoffset): EACCES
> (XEN) d1v1 Unhandled nested vmexit: reason 51
> (XEN) domain_crash called from vvmx.c:2671
> (XEN) Domain 1 (vcpu#1) crashed on cpu#2:
>
> 51 is the RDTSCP intercept. It seems that noone has ever tried executing a
> RDTSCP instruction in nested virt yet... which goes to show how untested this
> all is.
>
> Can you see about giving this patch a spin?
>
> ~Andrew
>
> 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;
Hi Andrew,
This patch works for me. The L2 domU boots successfully.
Thank you!
-- Chris
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prev parent reply other threads:[~2019-10-02 20:56 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <aecc7e18-40ff-8bb8-467c-24bfe99ee8f1@prgmr.com>
[not found] ` <470f5ce1-d43f-a5dd-a00d-e2ec339b06c0@suse.com>
2019-10-02 16:50 ` [Xen-devel] Crash with nested HVM and Linux v5.1+ Chris Brannon
2019-10-02 17:41 ` Andrew Cooper
2019-10-02 20:55 ` Chris Brannon [this message]
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