From: "Jürgen Groß" <jgross@suse.com>
To: Andrew Cooper <andrew.cooper3@citrix.com>,
xen-devel@lists.xenproject.org, x86@kernel.org,
linux-kernel@vger.kernel.org
Cc: Thomas Gleixner <tglx@linutronix.de>,
Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>,
"H. Peter Anvin" <hpa@zytor.com>,
Boris Ostrovsky <boris.ostrovsky@oracle.com>,
Stefano Stabellini <sstabellini@kernel.org>,
stable@vger.kernel.org
Subject: Re: [PATCH] x86/xen: avoid warning in Xen pv guest with CONFIG_AMD_MEM_ENCRYPT enabled
Date: Tue, 26 Jan 2021 06:12:42 +0100 [thread overview]
Message-ID: <aebac64f-a807-f3c6-1738-f14a4470efe3@suse.com> (raw)
In-Reply-To: <e49727ce-80b6-9eb6-8bd7-a4ce63c693e0@citrix.com>
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On 25.01.21 18:26, Andrew Cooper wrote:
> On 25/01/2021 14:00, Juergen Gross wrote:
>> diff --git a/arch/x86/xen/enlighten_pv.c b/arch/x86/xen/enlighten_pv.c
>> index 4409306364dc..82948251f57b 100644
>> --- a/arch/x86/xen/enlighten_pv.c
>> +++ b/arch/x86/xen/enlighten_pv.c
>> @@ -583,6 +583,14 @@ DEFINE_IDTENTRY_RAW(xenpv_exc_debug)
>> exc_debug(regs);
>> }
>>
>> +#ifdef CONFIG_AMD_MEM_ENCRYPT
>> +DEFINE_IDTENTRY_RAW(xenpv_exc_vmm_communication)
>> +{
>> + /* This should never happen and there is no way to handle it. */
>> + panic("X86_TRAP_VC in Xen PV mode.");
>
> Honestly, exactly the same is true of #VE, #HV and #SX.
>
> What we do in the hypervisor is wire up one handler for all unknown
> exceptions (to avoid potential future #DF issues) leading to a panic.
> Wouldn't it be better to do this unconditionally, especially as #GP/#NP
> doesn't work for PV guests for unregistered callbacks, rather than
> fixing up piecewise like this?
I agree it would be better to have a "catch all unknown" handler.
I'll have a try how this would look like.
Juergen
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prev parent reply other threads:[~2021-01-26 23:17 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-01-25 14:00 [PATCH] x86/xen: avoid warning in Xen pv guest with CONFIG_AMD_MEM_ENCRYPT enabled Juergen Gross
2021-01-25 17:26 ` Andrew Cooper
2021-01-26 5:12 ` Jürgen Groß [this message]
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