linux-kernel - VMX HOST_RIP target alignment

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Message-ID: <Y3adkSe/J70PqUyt@p183>
Date:   Thu, 17 Nov 2022 23:46:09 +0300
From:   Alexey Dobriyan <adobriyan@...il.com>
To:     kvm@...r.kernel.org
Cc:     linux-kernel@...r.kernel.org, jpoimboe@...nel.org,
        pbonzini@...hat.com, x86@...nel.org
Subject: VMX HOST_RIP target alignment

One of the side effects of fixing retbleed for VMX was demoting
HOST_RIP target from honorable function to a lowly label:

	-SYM_FUNC_START(vmx_vmexit)
	+SYM_INNER_LABEL(vmx_vmexit, SYM_L_GLOBAL)

ffffffff81243c49:       0f 01 c2                vmlaunch
ffffffff81243c4c:       e9 a7 00 00 00          jmp    ffffffff81243cf8 <vmx_vmexit+0xa7>

ffffffff81243c51 <vmx_vmexit>:
ffffffff81243c51:       50                      push   rax

Now I've never measured VM exit latency but is it important to align it
at 16 bytes like Intel recommends for functions?

	vmalexey