From mboxrd@z Thu Jan  1 00:00:00 1970
From: Radim =?utf-8?B?S3LEjW3DocWZ?= <rkrcmar@redhat.com>
Subject: Re: [PART1 RFC v2 07/10] svm: Add VMEXIT handlers for AVIC
Date: Tue, 8 Mar 2016 23:05:41 +0100
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Cc: Suravee Suthikulpanit <Suravee.Suthikulpanit@amd.com>,
	joro@8bytes.org, bp@alien8.de, gleb@kernel.org,
	alex.williamson@redhat.com, kvm@vger.kernel.org,
	linux-kernel@vger.kernel.org, wei@redhat.com,
	sherry.hurwitz@amd.com
To: Paolo Bonzini <pbonzini@redhat.com>
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2016-03-07 16:58+0100, Paolo Bonzini:
>> +	case AVIC_INCMP_IPI_ERR_INV_TARGET:
>> +		pr_err("%s: Invalid IPI target (icr=%#08x:%08x, idx=%u)\n",
>> +		       __func__, icrh, icrl, index);
>> +		BUG();
>> +		break;
>> +	case AVIC_INCMP_IPI_ERR_INV_BK_PAGE:
>> +		pr_err("%s: Invalid bk page (icr=%#08x:%08x, idx=%u)\n",
>> +		       __func__, icrh, icrl, index);
>> +		BUG();
>> +		break;
> 
> Please use WARN(1, "%s: Invalid bk page (icr=%#08x:%08x, idx=%u)\n",
> __func__, icrh, icrl, index) (and likewise for invalid target) instead
> of BUG().

I think that if we hit one of these, then WARNs would just flood the
log.  I'd prefer WARN_ONCE on AVIC_INCMP_IPI_ERR_INV_BK_PAGE.
(Btw. aren't icr and idx are pointless on this error?  and the function
 name should be printed by WARN.)

Invalid target is triggerable by the guest (by sending IPI to a
non-existent LAPIC), so warning log level seems too severe.
pr_info_ratelimited() or nothing would be better.