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    Subject[tip: x86/paravirt] x86/paravirt: Ensure proper alignment
    The following commit has been merged into the x86/paravirt branch of tip:

    Commit-ID: f92ff8f5dca2acfa475842c71212657b0703c3be
    Gitweb: https://git.kernel.org/tip/f92ff8f5dca2acfa475842c71212657b0703c3be
    Author: Thomas Gleixner <tglx@linutronix.de>
    AuthorDate: Thu, 15 Sep 2022 13:10:40 +02:00
    Committer: Borislav Petkov <bp@suse.de>
    CommitterDate: Wed, 21 Sep 2022 12:30:16 +02:00

    x86/paravirt: Ensure proper alignment

    The entries in the .parainstructions sections are 8 byte aligned and the
    corresponding C struct paravirt_patch_site makes the array offset 16
    bytes.

    Though the pushed entries are only using 12 bytes, __parainstructions_end
    is therefore 4 bytes short.

    That works by chance because it's only used in a loop:

    for (p = start; p < end; p++)

    But this falls flat when calculating the number of elements:

    n = end - start

    That's obviously off by one.

    Ensure that the gap is filled and the last entry is occupying 16 bytes.

    [ bp: Add the proper struct and section names. ]

    Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
    Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
    Signed-off-by: Borislav Petkov <bp@suse.de>
    Reviewed-by: Juergen Gross <jgross@suse.com>
    Link: https://lore.kernel.org/r/20220915111142.992398801@infradead.org
    ---
    arch/x86/include/asm/paravirt.h | 1 +
    arch/x86/include/asm/paravirt_types.h | 1 +
    2 files changed, 2 insertions(+)

    diff --git a/arch/x86/include/asm/paravirt.h b/arch/x86/include/asm/paravirt.h
    index 964442b..2a0b8dd 100644
    --- a/arch/x86/include/asm/paravirt.h
    +++ b/arch/x86/include/asm/paravirt.h
    @@ -743,6 +743,7 @@ extern void default_banner(void);
    word 771b; \
    .byte ptype; \
    .byte 772b-771b; \
    + _ASM_ALIGN; \
    .popsection


    diff --git a/arch/x86/include/asm/paravirt_types.h b/arch/x86/include/asm/paravirt_types.h
    index 89df6c6..27b036a 100644
    --- a/arch/x86/include/asm/paravirt_types.h
    +++ b/arch/x86/include/asm/paravirt_types.h
    @@ -294,6 +294,7 @@ extern struct paravirt_patch_template pv_ops;
    " .byte " type "\n" \
    " .byte 772b-771b\n" \
    " .short " clobber "\n" \
    + _ASM_ALIGN "\n" \
    ".popsection\n"

    /* Generate patchable code, with the default asm parameters. */
    \
     
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