From: Jan Beulich <jbeulich@suse.com>
To: "Roger Pau Monné" <roger@xenproject.org>,
"Ross Lagerwall" <ross.lagerwall@citrix.com>
Cc: xen-devel@lists.xenproject.org, Paul Durrant <paul@xen.org>,
Andrew Cooper <andrew.cooper3@citrix.com>,
Teddy Astie <teddy.astie@vates.tech>,
Anthony PERARD <anthony.perard@vates.tech>,
Michal Orzel <michal.orzel@amd.com>,
Julien Grall <julien@xen.org>,
Stefano Stabellini <sstabellini@kernel.org>
Subject: Re: [PATCH v2 2/3] x86/viridian: Implement synthetic timer direct mode
Date: Mon, 7 Sep 2026 10:57:06 +0200 [thread overview]
Message-ID: <4591a5ee-5fd9-4caa-95b3-81ef9078e600@suse.com> (raw)
In-Reply-To: <aprgh1uBTItcDvbg@macbook.local>
On 04.09.2026 17:15, Roger Pau Monné wrote:
> On Fri, Sep 04, 2026 at 03:15:15PM +0100, Ross Lagerwall wrote:
>> @@ -368,11 +379,18 @@ int viridian_time_wrmsr(struct vcpu *v, uint32_t idx, uint64_t val)
>> if ( !(viridian_feature_mask(d) & HVMPV_stimer) )
>> return X86EMUL_EXCEPTION;
>>
>> + new.as_uint64 = val;
>> + if ( new.direct_mode &&
>> + !(viridian_feature_mask(d) & HVMPV_stimer_direct) )
>> + return X86EMUL_EXCEPTION;
>
> Do we know whether native HyperV also injects a #GP in case of setting
> reserved bits on the register?
>
> To keep the previous behavior, should Xen silently ignore the setting
> when not supported, like it did in the past?
I think so, yes (and I thought I had expressed this also in the v1 comments,
but apparently not, or not sufficiently clearly).
Jan
next prev parent reply other threads:[~2026-09-07 8:57 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-09-04 14:15 [PATCH v2 0/3] Viridian changes for Hyper-V as a guest Ross Lagerwall
2026-09-04 14:15 ` [PATCH v2 1/3] x86/viridian: Workaround Hyper-V GP fault writing to MSR Ross Lagerwall
2026-09-04 14:53 ` Roger Pau Monné
2026-09-08 9:26 ` Ross Lagerwall
2026-09-04 14:15 ` [PATCH v2 2/3] x86/viridian: Implement synthetic timer direct mode Ross Lagerwall
2026-09-04 15:15 ` Roger Pau Monné
2026-09-07 8:57 ` Jan Beulich [this message]
2026-09-09 10:59 ` Ross Lagerwall
2026-09-07 9:02 ` Jan Beulich
2026-09-04 14:15 ` [PATCH v2 3/3] tools/libxl: Add support for Viridian stimer " Ross Lagerwall
2026-09-04 23:20 ` Tu Dinh
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