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Date: Fri, 3 Jan 2014 14:38:24 -0500
From: Konrad Rzeszutek Wilk <konrad.wilk@...cle.com>
To: xen-devel@...ts.xenproject.org, linux-kernel@...r.kernel.org,
boris.ostrovsky@...cle.com, stefano.stabellini@...citrix.com,
david.vrabel@...rix.com
Cc: hpa@...or.com, Mukesh Rathor <mukesh.rathor@...cle.com>,
Konrad Rzeszutek Wilk <konrad.wilk@...cle.com>
Subject: [PATCH v13 07/19] xen/pvh: MMU changes for PVH (v2)
From: Mukesh Rathor <mukesh.rathor@...cle.com>
.. which are surprinsingly small compared to the amount for PV code.
PVH uses mostly native mmu ops, we leave the generic (native_*) for
the majority and just overwrite the baremetal with the ones we need.
At startup, we are running with pre-allocated page-tables
courtesy of the tool-stack. But we still need to graft them
in the Linux initial pagetables. However there is no need to
unpin/pin and change them to R/O or R/W.
Note that the xen_pagetable_init due to 7836fec9d0994cc9c9150c5a33f0eb0eb08a335a
"xen/mmu/p2m: Refactor the xen_pagetable_init code." does not
need any changes - we just need to make sure that xen_post_allocator_init
does not alter the pvops from the default native one.
Signed-off-by: Mukesh Rathor <mukesh.rathor@...cle.com>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@...cle.com>
Acked-by: Stefano Stabellini <stefano.stabellini@...citrix.com>
---
arch/x86/xen/mmu.c | 81 +++++++++++++++++++++++++++++++-----------------------
1 file changed, 46 insertions(+), 35 deletions(-)
diff --git a/arch/x86/xen/mmu.c b/arch/x86/xen/mmu.c
index 9d74249..490ddb3 100644
--- a/arch/x86/xen/mmu.c
+++ b/arch/x86/xen/mmu.c
@@ -1757,6 +1757,10 @@ static void set_page_prot_flags(void *addr, pgprot_t prot, unsigned long flags)
unsigned long pfn = __pa(addr) >> PAGE_SHIFT;
pte_t pte = pfn_pte(pfn, prot);
+ /* For PVH no need to set R/O or R/W to pin them or unpin them. */
+ if (xen_feature(XENFEAT_auto_translated_physmap))
+ return;
+
if (HYPERVISOR_update_va_mapping((unsigned long)addr, pte, flags))
BUG();
}
@@ -1867,6 +1871,7 @@ static void __init check_pt_base(unsigned long *pt_base, unsigned long *pt_end,
* but that's enough to get __va working. We need to fill in the rest
* of the physical mapping once some sort of allocator has been set
* up.
+ * NOTE: for PVH, the page tables are native.
*/
void __init xen_setup_kernel_pagetable(pgd_t *pgd, unsigned long max_pfn)
{
@@ -1888,17 +1893,18 @@ void __init xen_setup_kernel_pagetable(pgd_t *pgd, unsigned long max_pfn)
/* Zap identity mapping */
init_level4_pgt[0] = __pgd(0);
- /* Pre-constructed entries are in pfn, so convert to mfn */
- /* L4[272] -> level3_ident_pgt
- * L4[511] -> level3_kernel_pgt */
- convert_pfn_mfn(init_level4_pgt);
-
- /* L3_i[0] -> level2_ident_pgt */
- convert_pfn_mfn(level3_ident_pgt);
- /* L3_k[510] -> level2_kernel_pgt
- * L3_i[511] -> level2_fixmap_pgt */
- convert_pfn_mfn(level3_kernel_pgt);
-
+ if (!xen_feature(XENFEAT_auto_translated_physmap)) {
+ /* Pre-constructed entries are in pfn, so convert to mfn */
+ /* L4[272] -> level3_ident_pgt
+ * L4[511] -> level3_kernel_pgt */
+ convert_pfn_mfn(init_level4_pgt);
+
+ /* L3_i[0] -> level2_ident_pgt */
+ convert_pfn_mfn(level3_ident_pgt);
+ /* L3_k[510] -> level2_kernel_pgt
+ * L3_i[511] -> level2_fixmap_pgt */
+ convert_pfn_mfn(level3_kernel_pgt);
+ }
/* We get [511][511] and have Xen's version of level2_kernel_pgt */
l3 = m2v(pgd[pgd_index(__START_KERNEL_map)].pgd);
l2 = m2v(l3[pud_index(__START_KERNEL_map)].pud);
@@ -1922,31 +1928,33 @@ void __init xen_setup_kernel_pagetable(pgd_t *pgd, unsigned long max_pfn)
copy_page(level2_fixmap_pgt, l2);
/* Note that we don't do anything with level1_fixmap_pgt which
* we don't need. */
+ if (!xen_feature(XENFEAT_auto_translated_physmap)) {
+ /* 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);
+
+ /* Pin down new L4 */
+ pin_pagetable_pfn(MMUEXT_PIN_L4_TABLE,
+ PFN_DOWN(__pa_symbol(init_level4_pgt)));
+
+ /* Unpin Xen-provided one */
+ pin_pagetable_pfn(MMUEXT_UNPIN_TABLE, PFN_DOWN(__pa(pgd)));
- /* 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);
-
- /* Pin down new L4 */
- pin_pagetable_pfn(MMUEXT_PIN_L4_TABLE,
- PFN_DOWN(__pa_symbol(init_level4_pgt)));
-
- /* Unpin Xen-provided one */
- pin_pagetable_pfn(MMUEXT_UNPIN_TABLE, PFN_DOWN(__pa(pgd)));
-
- /*
- * 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(init_level4_pgt));
- xen_mc_issue(PARAVIRT_LAZY_CPU);
+ /*
+ * 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(init_level4_pgt));
+ xen_mc_issue(PARAVIRT_LAZY_CPU);
+ } else
+ native_write_cr3(__pa(init_level4_pgt));
/* 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
@@ -2107,6 +2115,9 @@ static void xen_set_fixmap(unsigned idx, phys_addr_t phys, pgprot_t prot)
static void __init xen_post_allocator_init(void)
{
+ if (xen_feature(XENFEAT_auto_translated_physmap))
+ return;
+
pv_mmu_ops.set_pte = xen_set_pte;
pv_mmu_ops.set_pmd = xen_set_pmd;
pv_mmu_ops.set_pud = xen_set_pud;
--
1.8.3.1
--
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