From: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
To: linux-kernel@vger.kernel.org, xen-devel@lists.xensource.com
Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Subject: [PATCH 07/11] xen/mmu: Recycle the Xen provided L4, L3, and L2 pages
Date: Thu, 16 Aug 2012 12:03:25 -0400 [thread overview]
Message-ID: <1345133009-21941-8-git-send-email-konrad.wilk@oracle.com> (raw)
In-Reply-To: <1345133009-21941-1-git-send-email-konrad.wilk@oracle.com>
As we are not using them. We end up only using the L1 pagetables
and grafting those to our page-tables.
[v1: Per Stefano's suggestion squashed two commits]
[v2: Per Stefano's suggestion simplified loop]
[v3: Fix smatch warnings]
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
---
arch/x86/xen/mmu.c | 40 +++++++++++++++++++++++++++++++++-------
1 files changed, 33 insertions(+), 7 deletions(-)
diff --git a/arch/x86/xen/mmu.c b/arch/x86/xen/mmu.c
index a59070b..bd92c82 100644
--- a/arch/x86/xen/mmu.c
+++ b/arch/x86/xen/mmu.c
@@ -1708,7 +1708,20 @@ static void convert_pfn_mfn(void *v)
for (i = 0; i < PTRS_PER_PTE; i++)
pte[i] = xen_make_pte(pte[i].pte);
}
-
+static void __init check_pt_base(unsigned long *pt_base, unsigned long *pt_end,
+ unsigned long addr)
+{
+ if (*pt_base == PFN_DOWN(__pa(addr))) {
+ set_page_prot((void *)addr, PAGE_KERNEL);
+ clear_page((void *)addr);
+ (*pt_base)++;
+ }
+ if (*pt_end == PFN_DOWN(__pa(addr))) {
+ set_page_prot((void *)addr, PAGE_KERNEL);
+ clear_page((void *)addr);
+ (*pt_end)--;
+ }
+}
/*
* Set up the initial kernel pagetable.
*
@@ -1724,6 +1737,9 @@ void __init xen_setup_kernel_pagetable(pgd_t *pgd, unsigned long max_pfn)
{
pud_t *l3;
pmd_t *l2;
+ unsigned long addr[3];
+ unsigned long pt_base, pt_end;
+ unsigned i;
/* max_pfn_mapped is the last pfn mapped in the initial memory
* mappings. Considering that on Xen after the kernel mappings we
@@ -1731,6 +1747,9 @@ void __init xen_setup_kernel_pagetable(pgd_t *pgd, unsigned long max_pfn)
* set max_pfn_mapped to the last real pfn mapped. */
max_pfn_mapped = PFN_DOWN(__pa(xen_start_info->mfn_list));
+ pt_base = PFN_DOWN(__pa(xen_start_info->pt_base));
+ pt_end = PFN_DOWN(__pa(xen_start_info->pt_base + (xen_start_info->nr_pt_frames * PAGE_SIZE)));
+
/* Zap identity mapping */
init_level4_pgt[0] = __pgd(0);
@@ -1749,6 +1768,9 @@ void __init xen_setup_kernel_pagetable(pgd_t *pgd, unsigned long max_pfn)
l3 = m2v(pgd[pgd_index(__START_KERNEL_map)].pgd);
l2 = m2v(l3[pud_index(__START_KERNEL_map)].pud);
+ addr[0] = (unsigned long)pgd;
+ addr[1] = (unsigned long)l3;
+ addr[2] = (unsigned long)l2;
/* Graft it onto L4[272][0]. Note that we creating an aliasing problem:
* Both L4[272][0] and L4[511][511] have entries that point to the same
* L2 (PMD) tables. Meaning that if you modify it in __va space
@@ -1782,20 +1804,24 @@ void __init xen_setup_kernel_pagetable(pgd_t *pgd, unsigned long max_pfn)
/* Unpin Xen-provided one */
pin_pagetable_pfn(MMUEXT_UNPIN_TABLE, PFN_DOWN(__pa(pgd)));
- /* Switch over */
- pgd = init_level4_pgt;
-
/*
* At this stage there can be no user pgd, and no page
* structure to attach it to, so make sure we just set kernel
* pgd.
*/
xen_mc_batch();
- __xen_write_cr3(true, __pa(pgd));
+ __xen_write_cr3(true, __pa(init_level4_pgt));
xen_mc_issue(PARAVIRT_LAZY_CPU);
- memblock_reserve(__pa(xen_start_info->pt_base),
- xen_start_info->nr_pt_frames * PAGE_SIZE);
+ /* We can't that easily rip out L3 and L2, as the Xen pagetables are
+ * set out this way: [L4], [L1], [L2], [L3], [L1], [L1] ... for
+ * the initial domain. For guests using the toolstack, they are in:
+ * [L4], [L3], [L2], [L1], [L1], order .. */
+ for (i = 0; i < ARRAY_SIZE(addr); i++)
+ check_pt_base(&pt_base, &pt_end, addr[i]);
+
+ /* Our (by three pages) smaller Xen pagetable that we are using */
+ memblock_reserve(PFN_PHYS(pt_base), (pt_end - pt_base) * PAGE_SIZE);
}
#else /* !CONFIG_X86_64 */
static RESERVE_BRK_ARRAY(pmd_t, initial_kernel_pmd, PTRS_PER_PMD);
--
1.7.7.6
next prev parent reply other threads:[~2012-08-16 16:14 UTC|newest]
Thread overview: 43+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-08-16 16:03 [PATCH] Boot PV guests with more than 128GB (v3) for v3.7 Konrad Rzeszutek Wilk
2012-08-16 16:03 ` [PATCH 01/11] xen/p2m: Fix the comment describing the P2M tree Konrad Rzeszutek Wilk
2012-08-17 17:29 ` [Xen-devel] " Stefano Stabellini
2012-08-16 16:03 ` [PATCH 02/11] xen/x86: Use memblock_reserve for sensitive areas Konrad Rzeszutek Wilk
2012-08-17 17:35 ` [Xen-devel] " Stefano Stabellini
2012-08-20 14:13 ` Konrad Rzeszutek Wilk
2012-08-21 17:27 ` Q:pt_base in COMPAT mode offset by two pages. Was:Re: " Konrad Rzeszutek Wilk
2012-08-21 19:03 ` Konrad Rzeszutek Wilk
2012-08-22 10:48 ` Stefano Stabellini
2012-08-22 14:00 ` Konrad Rzeszutek Wilk
2012-08-22 14:12 ` Jan Beulich
2012-08-22 14:41 ` Stefano Stabellini
2012-08-22 14:57 ` Konrad Rzeszutek Wilk
2012-08-22 15:59 ` Jan Beulich
2012-08-22 16:21 ` Konrad Rzeszutek Wilk
2012-08-22 18:55 ` [Xen-devel] Q:pt_base in COMPAT mode offset by two pages. Was:Re: " Konrad Rzeszutek Wilk
2012-08-23 6:23 ` Jan Beulich
2012-08-16 16:03 ` [PATCH 03/11] xen/mmu: The xen_setup_kernel_pagetable doesn't need to return anything Konrad Rzeszutek Wilk
2012-08-16 16:03 ` [PATCH 04/11] xen/mmu: Provide comments describing the _ka and _va aliasing issue Konrad Rzeszutek Wilk
2012-08-16 16:03 ` [PATCH 05/11] xen/mmu: use copy_page instead of memcpy Konrad Rzeszutek Wilk
2012-08-16 16:03 ` [PATCH 06/11] xen/mmu: For 64-bit do not call xen_map_identity_early Konrad Rzeszutek Wilk
2012-08-17 17:41 ` [Xen-devel] " Stefano Stabellini
2012-08-17 17:45 ` Konrad Rzeszutek Wilk
2012-08-20 11:45 ` Stefano Stabellini
2012-08-20 11:53 ` Ian Campbell
2012-08-20 11:58 ` Stefano Stabellini
2012-08-20 12:06 ` Konrad Rzeszutek Wilk
2012-08-20 12:19 ` Stefano Stabellini
2012-08-23 15:40 ` Konrad Rzeszutek Wilk
2012-08-23 15:57 ` Stefano Stabellini
2012-08-16 16:03 ` Konrad Rzeszutek Wilk [this message]
2012-08-17 18:07 ` [Xen-devel] [PATCH 07/11] xen/mmu: Recycle the Xen provided L4, L3, and L2 pages Stefano Stabellini
2012-08-17 18:05 ` Konrad Rzeszutek Wilk
2012-08-16 16:03 ` [PATCH 08/11] xen/p2m: Add logic to revector a P2M tree to use __va leafs Konrad Rzeszutek Wilk
2012-08-16 16:03 ` [PATCH 09/11] xen/mmu: Copy and revector the P2M tree Konrad Rzeszutek Wilk
2012-08-16 16:03 ` [PATCH 10/11] xen/mmu: Remove from __ka space PMD entries for pagetables Konrad Rzeszutek Wilk
2012-08-16 16:03 ` [PATCH 11/11] xen/mmu: Release just the MFN list, not MFN list and part of pagetables Konrad Rzeszutek Wilk
2012-08-21 14:18 ` [Xen-devel] " Stefano Stabellini
2012-08-21 14:57 ` Konrad Rzeszutek Wilk
2012-08-21 15:27 ` Stefano Stabellini
2012-09-17 18:06 ` William Dauchy
2012-09-17 18:18 ` Konrad Rzeszutek Wilk
2012-08-17 17:39 ` [PATCH] Boot PV guests with more than 128GB (v3) for v3.7 Konrad Rzeszutek Wilk
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