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Message-Id: <3bb42a3945f477187ce4.1226603425@abulafia.goop.org>
Date: Thu, 13 Nov 2008 11:10:25 -0800
From: Jeremy Fitzhardinge <jeremy@...p.org>
To: Ingo Molnar <mingo@...e.hu>
Cc: linux-kernel@...r.kernel.org,
Xen-devel <xen-devel@...ts.xensource.com>,
the arch/x86 maintainers <x86@...nel.org>,
Ian Campbell <ian.campbell@...rix.com>
Subject: [PATCH 27 of 38] xen/dom0: use _PAGE_IOMAP in ioremap to do machine
mappings
In a Xen domain, ioremap operates on machine addresses, not
pseudo-physical addresses. We use _PAGE_IOMAP to determine whether a
mapping is intended for machine addresses.
Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@...rix.com>
---
arch/x86/include/asm/xen/page.h | 8 +----
arch/x86/xen/enlighten.c | 14 +++++++--
arch/x86/xen/mmu.c | 60 ++++++++++++++++++++++++++++++++++++++-
3 files changed, 73 insertions(+), 9 deletions(-)
diff --git a/arch/x86/include/asm/xen/page.h b/arch/x86/include/asm/xen/page.h
--- a/arch/x86/include/asm/xen/page.h
+++ b/arch/x86/include/asm/xen/page.h
@@ -112,13 +112,9 @@
*/
static inline unsigned long mfn_to_local_pfn(unsigned long mfn)
{
- extern unsigned long max_mapnr;
unsigned long pfn = mfn_to_pfn(mfn);
- if ((pfn < max_mapnr)
- && !xen_feature(XENFEAT_auto_translated_physmap)
- && (get_phys_to_machine(pfn) != mfn))
- return max_mapnr; /* force !pfn_valid() */
- /* XXX fixme; not true with sparsemem */
+ if (get_phys_to_machine(pfn) != mfn)
+ return -1; /* force !pfn_valid() */
return pfn;
}
diff --git a/arch/x86/xen/enlighten.c b/arch/x86/xen/enlighten.c
--- a/arch/x86/xen/enlighten.c
+++ b/arch/x86/xen/enlighten.c
@@ -1162,11 +1162,19 @@
#ifdef CONFIG_X86_LOCAL_APIC
case FIX_APIC_BASE: /* maps dummy local APIC */
#endif
+ /* All local page mappings */
pte = pfn_pte(phys, prot);
break;
+ case FIX_PARAVIRT_BOOTMAP:
+ /* This is an MFN, but it isn't an IO mapping from the
+ IO domain */
+ pte = mfn_pte(phys, prot);
+ break;
+
default:
- pte = mfn_pte(phys, prot);
+ /* By default, set_fixmap is used for hardware mappings */
+ pte = mfn_pte(phys, __pgprot(pgprot_val(prot) | _PAGE_IOMAP));
break;
}
@@ -1695,7 +1703,9 @@
/* Prevent unwanted bits from being set in PTEs. */
__supported_pte_mask &= ~_PAGE_GLOBAL;
- if (!xen_initial_domain())
+ if (xen_initial_domain())
+ __supported_pte_mask |= _PAGE_IOMAP;
+ else
__supported_pte_mask &= ~(_PAGE_PWT | _PAGE_PCD);
/* Don't do the full vcpu_info placement stuff until we have a
diff --git a/arch/x86/xen/mmu.c b/arch/x86/xen/mmu.c
--- a/arch/x86/xen/mmu.c
+++ b/arch/x86/xen/mmu.c
@@ -302,6 +302,28 @@
return PagePinned(page);
}
+static bool xen_iomap_pte(pte_t pte)
+{
+ return xen_initial_domain() && (pte_flags(pte) & _PAGE_IOMAP);
+}
+
+static void xen_set_iomap_pte(pte_t *ptep, pte_t pteval)
+{
+ struct multicall_space mcs;
+ struct mmu_update *u;
+
+ mcs = xen_mc_entry(sizeof(*u));
+ u = mcs.args;
+
+ /* ptep might be kmapped when using 32-bit HIGHPTE */
+ u->ptr = arbitrary_virt_to_machine(ptep).maddr;
+ u->val = pte_val_ma(pteval);
+
+ MULTI_mmu_update(mcs.mc, mcs.args, 1, NULL, DOMID_IO);
+
+ xen_mc_issue(PARAVIRT_LAZY_MMU);
+}
+
static void xen_extend_mmu_update(const struct mmu_update *update)
{
struct multicall_space mcs;
@@ -382,6 +404,11 @@
if (mm == &init_mm)
preempt_disable();
+ if (xen_iomap_pte(pteval)) {
+ xen_set_iomap_pte(ptep, pteval);
+ goto out;
+ }
+
ADD_STATS(set_pte_at, 1);
// ADD_STATS(set_pte_at_pinned, xen_page_pinned(ptep));
ADD_STATS(set_pte_at_current, mm == current->mm);
@@ -454,8 +481,25 @@
return val;
}
+static pteval_t iomap_pte(pteval_t val)
+{
+ if (val & _PAGE_PRESENT) {
+ unsigned long pfn = (val & PTE_PFN_MASK) >> PAGE_SHIFT;
+ pteval_t flags = val & PTE_FLAGS_MASK;
+
+ /* We assume the pte frame number is a MFN, so
+ just use it as-is. */
+ val = ((pteval_t)pfn << PAGE_SHIFT) | flags;
+ }
+
+ return val;
+}
+
pteval_t xen_pte_val(pte_t pte)
{
+ if (xen_initial_domain() && (pte.pte & _PAGE_IOMAP))
+ return pte.pte;
+
return pte_mfn_to_pfn(pte.pte);
}
@@ -466,7 +510,11 @@
pte_t xen_make_pte(pteval_t pte)
{
- pte = pte_pfn_to_mfn(pte);
+ if (unlikely(xen_initial_domain() && (pte & _PAGE_IOMAP)))
+ pte = iomap_pte(pte);
+ else
+ pte = pte_pfn_to_mfn(pte);
+
return native_make_pte(pte);
}
@@ -519,6 +567,11 @@
void xen_set_pte(pte_t *ptep, pte_t pte)
{
+ if (xen_iomap_pte(pte)) {
+ xen_set_iomap_pte(ptep, pte);
+ return;
+ }
+
ADD_STATS(pte_update, 1);
// ADD_STATS(pte_update_pinned, xen_page_pinned(ptep));
ADD_STATS(pte_update_batched, paravirt_get_lazy_mode() == PARAVIRT_LAZY_MMU);
@@ -535,6 +588,11 @@
#ifdef CONFIG_X86_PAE
void xen_set_pte_atomic(pte_t *ptep, pte_t pte)
{
+ if (xen_iomap_pte(pte)) {
+ xen_set_iomap_pte(ptep, pte);
+ return;
+ }
+
set_64bit((u64 *)ptep, native_pte_val(pte));
}
--
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