On Tue, 31 Dec 2013, Konrad Rzeszutek Wilk wrote:
> The revector and copying of the P2M only happens when
> !auto-xlat and on 64-bit builds. It is not obvious from
> the code, so lets have seperate 32 and 64-bit functions.
>
> We also invert the check for auto-xlat to make the code
> flow simpler.
>
> Suggested-by: Stefano Stabellini <stefano.stabell...@eu.citrix.com>
> Signed-off-by: Konrad Rzeszutek Wilk <konrad.w...@oracle.com>
> ---
> arch/x86/xen/mmu.c | 73
> ++++++++++++++++++++++++++++++------------------------
> 1 file changed, 40 insertions(+), 33 deletions(-)
>
> diff --git a/arch/x86/xen/mmu.c b/arch/x86/xen/mmu.c
> index ce563be..d792a69 100644
> --- a/arch/x86/xen/mmu.c
> +++ b/arch/x86/xen/mmu.c
> @@ -1198,44 +1198,40 @@ static void __init xen_cleanhighmap(unsigned long
> vaddr,
> * instead of somewhere later and be confusing. */
> xen_mc_flush();
> }
> -#endif
> -static void __init xen_pagetable_init(void)
> +static void __init xen_pagetable_p2m_copy(void)
> {
> -#ifdef CONFIG_X86_64
> unsigned long size;
> unsigned long addr;
> -#endif
> - paging_init();
> - xen_setup_shared_info();
> -#ifdef CONFIG_X86_64
> - if (!xen_feature(XENFEAT_auto_translated_physmap)) {
> - unsigned long new_mfn_list;
> + unsigned long new_mfn_list;
> +
> + if (xen_feature(XENFEAT_auto_translated_physmap))
> + return;
> +
> + size = PAGE_ALIGN(xen_start_info->nr_pages * sizeof(unsigned long));
> +
> + /* On 32-bit, we get zero so this never gets executed. */
Given that this code is already ifdef'ed CONFIG_X86_64, this comment
should be removed.
> + new_mfn_list = xen_revector_p2m_tree();
I take from the comment that new_mfn_list must not be zero. Maybe we
want a BUG_ON or a WARN_ON?
> + if (new_mfn_list && new_mfn_list != xen_start_info->mfn_list) {
> + /* using __ka address and sticking INVALID_P2M_ENTRY! */
> + memset((void *)xen_start_info->mfn_list, 0xff, size);
> +
> + /* We should be in __ka space. */
> + BUG_ON(xen_start_info->mfn_list < __START_KERNEL_map);
> + addr = xen_start_info->mfn_list;
> + /* We roundup to the PMD, which means that if anybody at this
> stage is
> + * using the __ka address of xen_start_info or
> xen_start_info->shared_info
> + * they are in going to crash. Fortunatly we have already
> revectored
> + * in xen_setup_kernel_pagetable and in xen_setup_shared_info.
> */
> + size = roundup(size, PMD_SIZE);
> + xen_cleanhighmap(addr, addr + size);
>
> size = PAGE_ALIGN(xen_start_info->nr_pages * sizeof(unsigned
> long));
> + memblock_free(__pa(xen_start_info->mfn_list), size);
> + /* And revector! Bye bye old array */
> + xen_start_info->mfn_list = new_mfn_list;
> + } else
> + return;
This was a normal condition when the function was executed on both
x86_64 and x86_32. Now that it is only executed on x86_64, is it still
the case?
> - /* On 32-bit, we get zero so this never gets executed. */
> - new_mfn_list = xen_revector_p2m_tree();
> - if (new_mfn_list && new_mfn_list != xen_start_info->mfn_list) {
> - /* using __ka address and sticking INVALID_P2M_ENTRY! */
> - memset((void *)xen_start_info->mfn_list, 0xff, size);
> -
> - /* We should be in __ka space. */
> - BUG_ON(xen_start_info->mfn_list < __START_KERNEL_map);
> - addr = xen_start_info->mfn_list;
> - /* We roundup to the PMD, which means that if anybody
> at this stage is
> - * using the __ka address of xen_start_info or
> xen_start_info->shared_info
> - * they are in going to crash. Fortunatly we have
> already revectored
> - * in xen_setup_kernel_pagetable and in
> xen_setup_shared_info. */
> - size = roundup(size, PMD_SIZE);
> - xen_cleanhighmap(addr, addr + size);
> -
> - size = PAGE_ALIGN(xen_start_info->nr_pages *
> sizeof(unsigned long));
> - memblock_free(__pa(xen_start_info->mfn_list), size);
> - /* And revector! Bye bye old array */
> - xen_start_info->mfn_list = new_mfn_list;
> - } else
> - goto skip;
> - }
> /* At this stage, cleanup_highmap has already cleaned __ka space
> * from _brk_limit way up to the max_pfn_mapped (which is the end of
> * the ramdisk). We continue on, erasing PMD entries that point to page
> @@ -1255,8 +1251,19 @@ static void __init xen_pagetable_init(void)
> * anything at this stage. */
> xen_cleanhighmap(MODULES_VADDR, roundup(MODULES_VADDR, PUD_SIZE) - 1);
> #endif
> -skip:
> +}
> +#else
> +static void __init xen_pagetable_p2m_copy(void)
> +{
> + /* Nada! */
> +}
> #endif
> +
> +static void __init xen_pagetable_init(void)
> +{
> + paging_init();
> + xen_setup_shared_info();
> + xen_pagetable_p2m_copy();
> xen_post_allocator_init();
> }
> static void xen_write_cr2(unsigned long cr2)
> --
> 1.8.3.1
>
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