linux-kernel - Re: [PATCH hyperv-next v3] x86/hyperv: Fix APIC ID and VP index confusion in hv_snp_boot

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Message-ID: <7f9212eb-f8c1-4f7b-a268-e7e4161fa1a9@linux.microsoft.com>
Date: Tue, 6 May 2025 08:46:44 -0700
From: Roman Kisel <romank@...ux.microsoft.com>
To: Wei Liu <wei.liu@...nel.org>
Cc: bp@...en8.de, dave.hansen@...ux.intel.com, decui@...rosoft.com,
 haiyangz@...rosoft.com, hpa@...or.com, kys@...rosoft.com,
 mikelley@...rosoft.com, mingo@...hat.com, tglx@...utronix.de,
 tiala@...rosoft.com, linux-hyperv@...r.kernel.org,
 linux-kernel@...r.kernel.org, x86@...nel.org, apais@...rosoft.com,
 benhill@...rosoft.com, bperkins@...rosoft.com, sunilmut@...rosoft.com
Subject: Re: [PATCH hyperv-next v3] x86/hyperv: Fix APIC ID and VP index
 confusion in hv_snp_boot_ap()



On 5/5/2025 11:28 PM, Wei Liu wrote:
> On Mon, Apr 28, 2025 at 11:27:05AM -0700, Roman Kisel wrote:
>> To start an application processor in SNP-isolated guest, a hypercall
>> is used that takes a virtual processor index. The hv_snp_boot_ap()
>> function uses that START_VP hypercall but passes as VP index to it
>> what it receives as a wakeup_secondary_cpu_64 callback: the APIC ID.
>>
>> As those two aren't generally interchangeable, that may lead to hung
>> APs if the VP index and the APIC ID don't match up.
>>
>> Update the parameter names to avoid confusion as to what the parameter
>> is. Use the APIC ID to the VP index conversion to provide the correct
>> input to the hypercall.
>>
>> Cc: stable@...r.kernel.org
>> Fixes: 44676bb9d566 ("x86/hyperv: Add smp support for SEV-SNP guest")
>> Signed-off-by: Roman Kisel <romank@...ux.microsoft.com>
> 
> Unfortunately this patch fails to apply. Please send a new version based
> on the latest hyperv-next.
> 

Will do, thanks a lot for letting me know!!

> Thanks,
> Wei.

-- 
Thank you,
Roman