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SubjectRe: [Xen-devel] [PATCH 06/11] xen/mmu: For 64-bit do not call xen_map_identity_early
On Thu, 23 Aug 2012, Konrad Rzeszutek Wilk wrote:
> >From 43fd7a5d9ecd31c2fc26851523cd4b5f7650fb39 Mon Sep 17 00:00:00 2001
> From: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
> Date: Thu, 12 Jul 2012 13:59:36 -0400
> Subject: [PATCH] xen/mmu: For 64-bit do not call xen_map_identity_early
>
> B/c we do not need it. During the startup the Xen provides
^ remove the
> us with all the initial memory mapped that we need to function.
>
> The initial memory mapped is up to the bootstack, which means
> we can reference using __ka up to 4.f):

Thanks, that is what I was looking for.

> (from xen/interface/xen.h):
>
> 4. This the order of bootstrap elements in the initial virtual region:
> a. relocated kernel image
> b. initial ram disk [mod_start, mod_len]
> c. list of allocated page frames [mfn_list, nr_pages]
> d. start_info_t structure [register ESI (x86)]
> e. bootstrap page tables [pt_base, CR3 (x86)]
> f. bootstrap stack [register ESP (x86)]
>
> (initial ram disk may be ommitted).
>
> [v1: More comments in git commit]
> Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>

Acked-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com>


> ---
> arch/x86/xen/mmu.c | 11 +++++------
> 1 files changed, 5 insertions(+), 6 deletions(-)
>
> diff --git a/arch/x86/xen/mmu.c b/arch/x86/xen/mmu.c
> index 7247e5a..a59070b 100644
> --- a/arch/x86/xen/mmu.c
> +++ b/arch/x86/xen/mmu.c
> @@ -84,6 +84,7 @@
> */
> DEFINE_SPINLOCK(xen_reservation_lock);
>
> +#ifdef CONFIG_X86_32
> /*
> * Identity map, in addition to plain kernel map. This needs to be
> * large enough to allocate page table pages to allocate the rest.
> @@ -91,7 +92,7 @@ DEFINE_SPINLOCK(xen_reservation_lock);
> */
> #define LEVEL1_IDENT_ENTRIES (PTRS_PER_PTE * 4)
> static RESERVE_BRK_ARRAY(pte_t, level1_ident_pgt, LEVEL1_IDENT_ENTRIES);
> -
> +#endif
> #ifdef CONFIG_X86_64
> /* l3 pud for userspace vsyscall mapping */
> static pud_t level3_user_vsyscall[PTRS_PER_PUD] __page_aligned_bss;
> @@ -1628,7 +1629,7 @@ static void set_page_prot(void *addr, pgprot_t prot)
> if (HYPERVISOR_update_va_mapping((unsigned long)addr, pte, 0))
> BUG();
> }
> -
> +#ifdef CONFIG_X86_32
> static void __init xen_map_identity_early(pmd_t *pmd, unsigned long max_pfn)
> {
> unsigned pmdidx, pteidx;
> @@ -1679,7 +1680,7 @@ static void __init xen_map_identity_early(pmd_t *pmd, unsigned long max_pfn)
>
> set_page_prot(pmd, PAGE_KERNEL_RO);
> }
> -
> +#endif
> void __init xen_setup_machphys_mapping(void)
> {
> struct xen_machphys_mapping mapping;
> @@ -1765,14 +1766,12 @@ void __init xen_setup_kernel_pagetable(pgd_t *pgd, unsigned long max_pfn)
> /* Note that we don't do anything with level1_fixmap_pgt which
> * we don't need. */
>
> - /* Set up identity map */
> - xen_map_identity_early(level2_ident_pgt, max_pfn);
> -
> /* Make pagetable pieces RO */
> set_page_prot(init_level4_pgt, PAGE_KERNEL_RO);
> set_page_prot(level3_ident_pgt, PAGE_KERNEL_RO);
> set_page_prot(level3_kernel_pgt, PAGE_KERNEL_RO);
> set_page_prot(level3_user_vsyscall, PAGE_KERNEL_RO);
> + set_page_prot(level2_ident_pgt, PAGE_KERNEL_RO);
> set_page_prot(level2_kernel_pgt, PAGE_KERNEL_RO);
> set_page_prot(level2_fixmap_pgt, PAGE_KERNEL_RO);
>
> --
> 1.7.7.6
>


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