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Message-ID: <6e0064bc-65c1-24f5-c29d-c1d1c027e2d3@citrix.com>
Date:   Tue, 26 Sep 2023 10:26:31 +0100
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From:   andrew.cooper3@citrix.com
Subject: Re: [PATCH v11 05/37] x86/trapnr: Add event type macros to
 <asm/trapnr.h>
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To:     Nikolay Borisov <nik.borisov@suse.com>, Xin Li <xin3.li@intel.com>,
        linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org,
        linux-edac@vger.kernel.org, linux-hyperv@vger.kernel.org,
        kvm@vger.kernel.org, xen-devel@lists.xenproject.org
Cc:     tglx@linutronix.de, mingo@redhat.com, bp@alien8.de,
        dave.hansen@linux.intel.com, x86@kernel.org, hpa@zytor.com,
        luto@kernel.org, pbonzini@redhat.com, seanjc@google.com,
        peterz@infradead.org, jgross@suse.com, ravi.v.shankar@intel.com,
        mhiramat@kernel.org, jiangshanlai@gmail.com
References: <20230923094212.26520-1-xin3.li@intel.com>
 <20230923094212.26520-6-xin3.li@intel.com>
 <7acd7bb3-0406-4fd9-8396-835bfd951d87@suse.com>
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On 26/09/2023 9:10 am, Nikolay Borisov wrote:
> On 23.09.23 г. 12:41 ч., Xin Li wrote:
>> diff --git a/arch/x86/include/asm/trapnr.h
>> b/arch/x86/include/asm/trapnr.h
>> index f5d2325aa0b7..8d1154cdf787 100644
>> --- a/arch/x86/include/asm/trapnr.h
>> +++ b/arch/x86/include/asm/trapnr.h
>> @@ -2,6 +2,18 @@
>>   #ifndef _ASM_X86_TRAPNR_H
>>   #define _ASM_X86_TRAPNR_H
>>   +/*
>> + * Event type codes used by FRED, Intel VT-x and AMD SVM
>> + */
>> +#define EVENT_TYPE_EXTINT    0    // External interrupt
>> +#define EVENT_TYPE_RESERVED    1
>> +#define EVENT_TYPE_NMI        2    // NMI
>> +#define EVENT_TYPE_HWEXC    3    // Hardware originated traps,
>> exceptions
>> +#define EVENT_TYPE_SWINT    4    // INT n
>> +#define EVENT_TYPE_PRIV_SWEXC    5    // INT1
>> +#define EVENT_TYPE_SWEXC    6    // INTO, INT3
>
> nit: This turned into INTO (Oh) rather than INT0( zero) in v11

Yes, v11 corrected a bug in v10.

The INTO instruction is "INT on Overflow".  No zero involved.

INT3 is thusly named because it generates vector 3.  Similarly for INT1
although it had the unofficial name ICEBP long before INT1 got documented.

If INTO were to have a number, it would need to be 4, but it's behaviour
is conditional on the overflow flag, unlike INT3/1 which are
unconditional exceptions.

~Andrew