Received-SPF: pass (google.com: domain of linux-kernel+bounces-50710-linux.lists.archive=gmail.com@vger.kernel.org designates 2604:1380:45d1:ec00::1 as permitted sender) client-ip=2604:1380:45d1:ec00::1;
From: Vitaly Kuznetsov <vkuznets@redhat.com>
To: Sean Christopherson <seanjc@google.com>, kvm@vger.kernel.org, Paolo
 Bonzini <pbonzini@redhat.com>
Cc: David Woodhouse <dwmw@amazon.co.uk>, Jan Richter <jarichte@redhat.com>,
 linux-kernel@vger.kernel.org
Subject: Re: [PATCH] KVM: selftests: Compare wall time from xen shinfo
 against KVM_GET_CLOCK
In-Reply-To: <ZbvObrzoyZlay-Xg@google.com>
References: <20240111135901.1785096-1-vkuznets@redhat.com>
 <170666266419.3861766.8799090958259831473.b4-ty@google.com>
 <ZbvObrzoyZlay-Xg@google.com>
Date: Sat, 03 Feb 2024 00:27:45 +0100
Message-ID: <87r0huh2fi.fsf@redhat.com>
Precedence: bulk
MIME-Version: 1.0
Content-Type: text/plain

Sean Christopherson <seanjc@google.com> writes:

> On Tue, Jan 30, 2024, Sean Christopherson wrote:
>> On Thu, 11 Jan 2024 14:59:01 +0100, Vitaly Kuznetsov wrote:
>> > xen_shinfo_test is observed to be flaky failing sporadically with
>> > "VM time too old". With min_ts/max_ts debug print added:
>> > 
>> > Wall clock (v 3269818) 1704906491.986255664
>> > Time info 1: v 1282712 tsc 33530585736 time 14014430025 mul 3587552223 shift 4294967295 flags 1
>> > Time info 2: v 1282712 tsc 33530585736 time 14014430025 mul 3587552223 shift 4294967295 flags 1
>> > min_ts: 1704906491.986312153
>> > max_ts: 1704906506.001006963
>> > ==== Test Assertion Failure ====
>> >   x86_64/xen_shinfo_test.c:1003: cmp_timespec(&min_ts, &vm_ts) <= 0
>> >   pid=32724 tid=32724 errno=4 - Interrupted system call
>> >      1	0x00000000004030ad: main at xen_shinfo_test.c:1003
>> >      2	0x00007fca6b23feaf: ?? ??:0
>> >      3	0x00007fca6b23ff5f: ?? ??:0
>> >      4	0x0000000000405e04: _start at ??:?
>> >   VM time too old
>> > 
>> > [...]
>> 
>> Applied to kvm-x86 selftests.  David, please holler if you disagree with
>> any of the changes.  They look sane to me, but clock stuff ain't my forte.
>> 
>> Thanks!
>> 
>> [1/1] KVM: selftests: Compare wall time from xen shinfo against KVM_GET_CLOCK
>>       https://github.com/kvm-x86/linux/commit/a0868e7c5575
>
> FYI, I've dropped this as it looks like there will be a new version.

Thanks, indeed, I'll do do changes suggested by David in v2 but as I'm
traveling this weekend (FOSDEM calls!) please expect my posting Tuesday+
next week.

-- 
Vitaly