Message-ID: <68b180fa-75ee-08b9-aa6b-2afeac860462@amd.com>
Date:   Thu, 16 Feb 2023 14:50:09 +0100
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Subject: Re: [RFC PATCH V3 12/16] x86/sev: Add a #HV exception handler
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To:     Tianyu Lan <ltykernel@gmail.com>, luto@kernel.org,
        tglx@linutronix.de, mingo@redhat.com, bp@alien8.de,
        dave.hansen@linux.intel.com, x86@kernel.org, hpa@zytor.com,
        seanjc@google.com, pbonzini@redhat.com, jgross@suse.com,
        tiala@microsoft.com, kirill@shutemov.name,
        jiangshan.ljs@antgroup.com, peterz@infradead.org,
        ashish.kalra@amd.com, srutherford@google.com,
        akpm@linux-foundation.org, anshuman.khandual@arm.com,
        pawan.kumar.gupta@linux.intel.com, adrian.hunter@intel.com,
        daniel.sneddon@linux.intel.com, alexander.shishkin@linux.intel.com,
        sandipan.das@amd.com, ray.huang@amd.com, brijesh.singh@amd.com,
        michael.roth@amd.com, thomas.lendacky@amd.com,
        venu.busireddy@oracle.com, sterritt@google.com,
        tony.luck@intel.com, samitolvanen@google.com, fenghua.yu@intel.com
Cc:     linux-kernel@vger.kernel.org, kvm@vger.kernel.org,
        linux-hyperv@vger.kernel.org, linux-arch@vger.kernel.org
References: <20230122024607.788454-1-ltykernel@gmail.com>
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 <0098b974-7ceb-664a-aa53-afac8cc26d47@amd.com>
 <7dbc845a-0ada-f97a-ba50-a6b2c31ee9c0@gmail.com>
From:   "Gupta, Pankaj" <pankaj.gupta@amd.com>
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On 2/3/2023 8:27 AM, Tianyu Lan wrote:
> On 1/23/2023 3:33 PM, Gupta, Pankaj wrote:
>>
>>> + */
>>> +.macro idtentry_hv vector asmsym cfunc
>>> +SYM_CODE_START(\asmsym)
>>> +    UNWIND_HINT_IRET_REGS
>>> +    ASM_CLAC
>>
>> Did you get a chance to review the new instructions
>> added at the start similar to idtentry_vc and comments
>> added assuggested here?
>>
>> https://lore.kernel.org/lkml/16e50239-39b2-4fb4-5110-18f13ba197fe@amd.com/
> 
> Hi Pankaj:
>      Thanks for your reminder. Yes, CLD should be add after ASM_CLAC. 
> Will fix it.

Also it looks ENDBR also needs to be added before ASM_CLAC? as I also 
get this:

vmlinux.o: warning: objtool: asm_exc_hv_injection+0x0: 
UNWIND_HINT_IRET_REGS without ENDBR
vmlinux.o: warning: objtool: ibt_selftest+0x11: sibling call from 
callable instruction with modified stack frame
vmlinux.o: warning: objtool: ibt_selftest+0x1e: return with modified 
stack frame
vmlinux.o: warning: objtool: def_idts+0x1d8: data relocation to !ENDBR: 
asm_exc_hv_injection+0x0

Thanks,
Pankaj