[GIT 0/3] x86: remove kmap_atomic_pte paravirt op

[GIT 0/3] x86: remove kmap_atomic_pte paravirt op

[Ian Campbell]

The following changes since commit c1fd1b43831fa20c91cdd461342af8edf2e87c2f:
  Pekka Enberg (1):
        x86, mm: Unify kernel_physical_mapping_init() API

are available in the git repository at:

  git://xenbits.xensource.com/people/ianc/linux-2.6.git for-x86/mm

Ian Campbell (3):
      xen: disable highmem PTE allocation even when CONFIG_HIGHPTE=y
      vmi: disable highmem PTE allocation even when CONFIG_HIGHPTE=y
      x86: remove kmap_atomic_pte paravirt op.

 arch/x86/include/asm/highmem.h        |    4 ---
 arch/x86/include/asm/paravirt.h       |    9 --------
 arch/x86/include/asm/paravirt_types.h |    4 ---
 arch/x86/include/asm/pgtable_32.h     |    4 +-
 arch/x86/kernel/paravirt.c            |    4 ---
 arch/x86/kernel/vmi_32.c              |   35 ++++++--------------------------
 arch/x86/xen/enlighten.c              |    7 ++++++
 arch/x86/xen/mmu.c                    |   21 -------------------
 8 files changed, 16 insertions(+), 72 deletions(-)

[PATCH 1/3] xen: disable highmem PTE allocation even when CONFIG_HIGHPTE=y

[Ian Campbell]

There's a path in the pagefault code where the kernel deliberately
breaks its own locking rules by kmapping a high pte page without
holding the pagetable lock (in at least page_check_address). This
breaks Xen's ability to track the pinned/unpinned state of the
page. There does not appear to be a viable workaround for this
behaviour so simply disable HIGHPTE for all Xen guests.

Signed-off-by: Ian Campbell <ian.campbell@citrix.com>
Cc: Jeremy Fitzhardinge <jeremy@goop.org>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Pasi Kärkkäinen <pasik@iki.fi>
Cc: <stable@kernel.org> # .32.x: 14315592: Allow highmem user page tables to be disabled at boot time
Cc: <stable@kernel.org> # .32.x
Cc: <xen-devel@lists.xensource.com>
---
 arch/x86/xen/enlighten.c |    7 +++++++
 arch/x86/xen/mmu.c       |   11 ++++++-----
 2 files changed, 13 insertions(+), 5 deletions(-)

diff --git a/arch/x86/xen/enlighten.c b/arch/x86/xen/enlighten.c
index 36daccb..b607239 100644
--- a/arch/x86/xen/enlighten.c
+++ b/arch/x86/xen/enlighten.c
@@ -50,6 +50,7 @@
 #include <asm/traps.h>
 #include <asm/setup.h>
 #include <asm/desc.h>
+#include <asm/pgalloc.h>
 #include <asm/pgtable.h>
 #include <asm/tlbflush.h>
 #include <asm/reboot.h>
@@ -1094,6 +1095,12 @@ asmlinkage void __init xen_start_kernel(void)
 
 	__supported_pte_mask |= _PAGE_IOMAP;
 
+	/*
+	 * Prevent page tables from being allocated in highmem, even
+	 * if CONFIG_HIGHPTE is enabled.
+	 */
+	__userpte_alloc_gfp &= ~__GFP_HIGHMEM;
+
 	/* Work out if we support NX */
 	x86_configure_nx();
 
diff --git a/arch/x86/xen/mmu.c b/arch/x86/xen/mmu.c
index bf4cd6b..350a3de 100644
--- a/arch/x86/xen/mmu.c
+++ b/arch/x86/xen/mmu.c
@@ -1432,14 +1432,15 @@ static void *xen_kmap_atomic_pte(struct page *page, enum km_type type)
 {
 	pgprot_t prot = PAGE_KERNEL;
 
+	/*
+	 * We disable highmem allocations for page tables so we should never
+	 * see any calls to kmap_atomic_pte on a highmem page.
+	 */
+	BUG_ON(PageHighMem(page));
+
 	if (PagePinned(page))
 		prot = PAGE_KERNEL_RO;
 
-	if (0 && PageHighMem(page))
-		printk("mapping highpte %lx type %d prot %s\n",
-		       page_to_pfn(page), type,
-		       (unsigned long)pgprot_val(prot) & _PAGE_RW ? "WRITE" : "READ");
-
 	return kmap_atomic_prot(page, type, prot);
 }
 #endif
-- 
1.5.6.5

[PATCH 2/3] vmi: disable highmem PTE allocation even when CONFIG_HIGHPTE=y

[Ian Campbell]

Preventing HIGHPTE allocations under VMI will allow us to remove the
kmap_atomic_pte paravirt op.

Signed-off-by: Ian Campbell <ian.campbell@citrix.com>
Cc: Alok Kataria <akataria@vmware.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Jeremy Fitzhardinge <jeremy@goop.org>
---
 arch/x86/kernel/vmi_32.c |   23 +++++++++++------------
 1 files changed, 11 insertions(+), 12 deletions(-)

diff --git a/arch/x86/kernel/vmi_32.c b/arch/x86/kernel/vmi_32.c
index d430e4c..58aca86 100644
--- a/arch/x86/kernel/vmi_32.c
+++ b/arch/x86/kernel/vmi_32.c
@@ -33,6 +33,7 @@
 #include <asm/fixmap.h>
 #include <asm/apicdef.h>
 #include <asm/apic.h>
+#include <asm/pgalloc.h>
 #include <asm/processor.h>
 #include <asm/timer.h>
 #include <asm/vmi_time.h>
@@ -272,19 +273,11 @@ static void *vmi_kmap_atomic_pte(struct page *page, enum km_type type)
 	void *va = kmap_atomic(page, type);
 
 	/*
-	 * Internally, the VMI ROM must map virtual addresses to physical
-	 * addresses for processing MMU updates.  By the time MMU updates
-	 * are issued, this information is typically already lost.
-	 * Fortunately, the VMI provides a cache of mapping slots for active
-	 * page tables.
-	 *
-	 * We use slot zero for the linear mapping of physical memory, and
-	 * in HIGHPTE kernels, slot 1 and 2 for KM_PTE0 and KM_PTE1.
-	 *
-	 *  args:                 SLOT                 VA    COUNT PFN
+	 * We disable highmem allocations for page tables so we should never
+	 * see any calls to kmap_atomic_pte on a highmem page.
 	 */
-	BUG_ON(type != KM_PTE0 && type != KM_PTE1);
-	vmi_ops.set_linear_mapping((type - KM_PTE0)+1, va, 1, page_to_pfn(page));
+
+	BUG_ON(PageHighmem(page));
 
 	return va;
 }
@@ -640,6 +633,12 @@ static inline int __init activate_vmi(void)
 	u64 reloc;
 	const struct vmi_relocation_info *rel = (struct vmi_relocation_info *)&reloc;
 
+	/*
+	 * Prevent page tables from being allocated in highmem, even if
+	 * CONFIG_HIGHPTE is enabled.
+	 */
+	__userpte_alloc_gfp &= ~__GFP_HIGHMEM;
+
 	if (call_vrom_func(vmi_rom, vmi_init) != 0) {
 		printk(KERN_ERR "VMI ROM failed to initialize!");
 		return 0;
-- 
1.5.6.5

[PATCH 3/3] x86: remove kmap_atomic_pte paravirt op.

[Ian Campbell]

Now that both Xen and VMI disable allocations of PTE pages from high
memory this paravirt op serves no further purpose.

This effectively reverts ce6234b5 "add kmap_atomic_pte for mapping
highpte pages".

Signed-off-by: Ian Campbell <ian.campbell@citrix.com>
Cc: Alok Kataria <akataria@vmware.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Jeremy Fitzhardinge <jeremy@goop.org>
Cc: Ingo Molnar <mingo@elte.hu>
---
 arch/x86/include/asm/highmem.h        |    4 ----
 arch/x86/include/asm/paravirt.h       |    9 ---------
 arch/x86/include/asm/paravirt_types.h |    4 ----
 arch/x86/include/asm/pgtable_32.h     |    4 ++--
 arch/x86/kernel/paravirt.c            |    4 ----
 arch/x86/kernel/vmi_32.c              |   20 --------------------
 arch/x86/xen/mmu.c                    |   22 ----------------------
 7 files changed, 2 insertions(+), 65 deletions(-)

diff --git a/arch/x86/include/asm/highmem.h b/arch/x86/include/asm/highmem.h
index 014c2b8..a726650 100644
--- a/arch/x86/include/asm/highmem.h
+++ b/arch/x86/include/asm/highmem.h
@@ -66,10 +66,6 @@ void *kmap_atomic_pfn(unsigned long pfn, enum km_type type);
 void *kmap_atomic_prot_pfn(unsigned long pfn, enum km_type type, pgprot_t prot);
 struct page *kmap_atomic_to_page(void *ptr);
 
-#ifndef CONFIG_PARAVIRT
-#define kmap_atomic_pte(page, type)	kmap_atomic(page, type)
-#endif
-
 #define flush_cache_kmaps()	do { } while (0)
 
 extern void add_highpages_with_active_regions(int nid, unsigned long start_pfn,
diff --git a/arch/x86/include/asm/paravirt.h b/arch/x86/include/asm/paravirt.h
index dd59a85..5653f43 100644
--- a/arch/x86/include/asm/paravirt.h
+++ b/arch/x86/include/asm/paravirt.h
@@ -435,15 +435,6 @@ static inline void paravirt_release_pud(unsigned long pfn)
 	PVOP_VCALL1(pv_mmu_ops.release_pud, pfn);
 }
 
-#ifdef CONFIG_HIGHPTE
-static inline void *kmap_atomic_pte(struct page *page, enum km_type type)
-{
-	unsigned long ret;
-	ret = PVOP_CALL2(unsigned long, pv_mmu_ops.kmap_atomic_pte, page, type);
-	return (void *)ret;
-}
-#endif
-
 static inline void pte_update(struct mm_struct *mm, unsigned long addr,
 			      pte_t *ptep)
 {
diff --git a/arch/x86/include/asm/paravirt_types.h b/arch/x86/include/asm/paravirt_types.h
index b1e70d5..db9ef55 100644
--- a/arch/x86/include/asm/paravirt_types.h
+++ b/arch/x86/include/asm/paravirt_types.h
@@ -304,10 +304,6 @@ struct pv_mmu_ops {
 #endif	/* PAGETABLE_LEVELS == 4 */
 #endif	/* PAGETABLE_LEVELS >= 3 */
 
-#ifdef CONFIG_HIGHPTE
-	void *(*kmap_atomic_pte)(struct page *page, enum km_type type);
-#endif
-
 	struct pv_lazy_ops lazy_mode;
 
 	/* dom0 ops */
diff --git a/arch/x86/include/asm/pgtable_32.h b/arch/x86/include/asm/pgtable_32.h
index 01fd946..b422d22 100644
--- a/arch/x86/include/asm/pgtable_32.h
+++ b/arch/x86/include/asm/pgtable_32.h
@@ -54,10 +54,10 @@ extern void set_pmd_pfn(unsigned long, unsigned long, pgprot_t);
 	 in_irq() ? KM_IRQ_PTE :	\
 	 KM_PTE0)
 #define pte_offset_map(dir, address)					\
-	((pte_t *)kmap_atomic_pte(pmd_page(*(dir)), __KM_PTE) +		\
+	((pte_t *)kmap_atomic(pmd_page(*(dir)), __KM_PTE) +		\
 	 pte_index((address)))
 #define pte_offset_map_nested(dir, address)				\
-	((pte_t *)kmap_atomic_pte(pmd_page(*(dir)), KM_PTE1) +		\
+	((pte_t *)kmap_atomic(pmd_page(*(dir)), KM_PTE1) +		\
 	 pte_index((address)))
 #define pte_unmap(pte) kunmap_atomic((pte), __KM_PTE)
 #define pte_unmap_nested(pte) kunmap_atomic((pte), KM_PTE1)
diff --git a/arch/x86/kernel/paravirt.c b/arch/x86/kernel/paravirt.c
index 1b1739d..1db183e 100644
--- a/arch/x86/kernel/paravirt.c
+++ b/arch/x86/kernel/paravirt.c
@@ -428,10 +428,6 @@ struct pv_mmu_ops pv_mmu_ops = {
 	.ptep_modify_prot_start = __ptep_modify_prot_start,
 	.ptep_modify_prot_commit = __ptep_modify_prot_commit,
 
-#ifdef CONFIG_HIGHPTE
-	.kmap_atomic_pte = kmap_atomic,
-#endif
-
 #if PAGETABLE_LEVELS >= 3
 #ifdef CONFIG_X86_PAE
 	.set_pte_atomic = native_set_pte_atomic,
diff --git a/arch/x86/kernel/vmi_32.c b/arch/x86/kernel/vmi_32.c
index 58aca86..7dd599d 100644
--- a/arch/x86/kernel/vmi_32.c
+++ b/arch/x86/kernel/vmi_32.c
@@ -267,22 +267,6 @@ static void vmi_nop(void)
 {
 }
 
-#ifdef CONFIG_HIGHPTE
-static void *vmi_kmap_atomic_pte(struct page *page, enum km_type type)
-{
-	void *va = kmap_atomic(page, type);
-
-	/*
-	 * We disable highmem allocations for page tables so we should never
-	 * see any calls to kmap_atomic_pte on a highmem page.
-	 */
-
-	BUG_ON(PageHighmem(page));
-
-	return va;
-}
-#endif
-
 static void vmi_allocate_pte(struct mm_struct *mm, unsigned long pfn)
 {
 	vmi_ops.allocate_page(pfn, VMI_PAGE_L1, 0, 0, 0);
@@ -777,10 +761,6 @@ static inline int __init activate_vmi(void)
 
 	/* Set linear is needed in all cases */
 	vmi_ops.set_linear_mapping = vmi_get_function(VMI_CALL_SetLinearMapping);
-#ifdef CONFIG_HIGHPTE
-	if (vmi_ops.set_linear_mapping)
-		pv_mmu_ops.kmap_atomic_pte = vmi_kmap_atomic_pte;
-#endif
 
 	/*
 	 * These MUST always be patched.  Don't support indirect jumps
diff --git a/arch/x86/xen/mmu.c b/arch/x86/xen/mmu.c
index 350a3de..f9eb7de 100644
--- a/arch/x86/xen/mmu.c
+++ b/arch/x86/xen/mmu.c
@@ -1427,24 +1427,6 @@ static void xen_pgd_free(struct mm_struct *mm, pgd_t *pgd)
 #endif
 }
 
-#ifdef CONFIG_HIGHPTE
-static void *xen_kmap_atomic_pte(struct page *page, enum km_type type)
-{
-	pgprot_t prot = PAGE_KERNEL;
-
-	/*
-	 * We disable highmem allocations for page tables so we should never
-	 * see any calls to kmap_atomic_pte on a highmem page.
-	 */
-	BUG_ON(PageHighMem(page));
-
-	if (PagePinned(page))
-		prot = PAGE_KERNEL_RO;
-
-	return kmap_atomic_prot(page, type, prot);
-}
-#endif
-
 #ifdef CONFIG_X86_32
 static __init pte_t mask_rw_pte(pte_t *ptep, pte_t pte)
 {
@@ -1903,10 +1885,6 @@ static const struct pv_mmu_ops xen_mmu_ops __initdata = {
 	.alloc_pmd_clone = paravirt_nop,
 	.release_pmd = xen_release_pmd_init,
 
-#ifdef CONFIG_HIGHPTE
-	.kmap_atomic_pte = xen_kmap_atomic_pte,
-#endif
-
 #ifdef CONFIG_X86_64
 	.set_pte = xen_set_pte,
 #else
-- 
1.5.6.5

Re: [PATCH 3/3] x86: remove kmap_atomic_pte paravirt op.

[Alok Kataria]

On Fri, 2010-02-26 at 09:16 -0800, Ian Campbell wrote:
> Now that both Xen and VMI disable allocations of PTE pages from high
> memory this paravirt op serves no further purpose.

Acked-by: Alok N Kataria <akataria@vmware.com>

Thanks for doing this.

Alok
> 
> This effectively reverts ce6234b5 "add kmap_atomic_pte for mapping
> highpte pages".
> 
> Signed-off-by: Ian Campbell <ian.campbell@citrix.com>
> Cc: Alok Kataria <akataria@vmware.com>
> Cc: H. Peter Anvin <hpa@zytor.com>
> Cc: Jeremy Fitzhardinge <jeremy@goop.org>
> Cc: Ingo Molnar <mingo@elte.hu>
> ---
>  arch/x86/include/asm/highmem.h        |    4 ----
>  arch/x86/include/asm/paravirt.h       |    9 ---------
>  arch/x86/include/asm/paravirt_types.h |    4 ----
>  arch/x86/include/asm/pgtable_32.h     |    4 ++--
>  arch/x86/kernel/paravirt.c            |    4 ----
>  arch/x86/kernel/vmi_32.c              |   20 --------------------
>  arch/x86/xen/mmu.c                    |   22 ----------------------
>  7 files changed, 2 insertions(+), 65 deletions(-)
> 
> diff --git a/arch/x86/include/asm/highmem.h b/arch/x86/include/asm/highmem.h
> index 014c2b8..a726650 100644
> --- a/arch/x86/include/asm/highmem.h
> +++ b/arch/x86/include/asm/highmem.h
> @@ -66,10 +66,6 @@ void *kmap_atomic_pfn(unsigned long pfn, enum km_type type);
>  void *kmap_atomic_prot_pfn(unsigned long pfn, enum km_type type, pgprot_t prot);
>  struct page *kmap_atomic_to_page(void *ptr);
>  
> -#ifndef CONFIG_PARAVIRT
> -#define kmap_atomic_pte(page, type)	kmap_atomic(page, type)
> -#endif
> -
>  #define flush_cache_kmaps()	do { } while (0)
>  
>  extern void add_highpages_with_active_regions(int nid, unsigned long start_pfn,
> diff --git a/arch/x86/include/asm/paravirt.h b/arch/x86/include/asm/paravirt.h
> index dd59a85..5653f43 100644
> --- a/arch/x86/include/asm/paravirt.h
> +++ b/arch/x86/include/asm/paravirt.h
> @@ -435,15 +435,6 @@ static inline void paravirt_release_pud(unsigned long pfn)
>  	PVOP_VCALL1(pv_mmu_ops.release_pud, pfn);
>  }
>  
> -#ifdef CONFIG_HIGHPTE
> -static inline void *kmap_atomic_pte(struct page *page, enum km_type type)
> -{
> -	unsigned long ret;
> -	ret = PVOP_CALL2(unsigned long, pv_mmu_ops.kmap_atomic_pte, page, type);
> -	return (void *)ret;
> -}
> -#endif
> -
>  static inline void pte_update(struct mm_struct *mm, unsigned long addr,
>  			      pte_t *ptep)
>  {
> diff --git a/arch/x86/include/asm/paravirt_types.h b/arch/x86/include/asm/paravirt_types.h
> index b1e70d5..db9ef55 100644
> --- a/arch/x86/include/asm/paravirt_types.h
> +++ b/arch/x86/include/asm/paravirt_types.h
> @@ -304,10 +304,6 @@ struct pv_mmu_ops {
>  #endif	/* PAGETABLE_LEVELS == 4 */
>  #endif	/* PAGETABLE_LEVELS >= 3 */
>  
> -#ifdef CONFIG_HIGHPTE
> -	void *(*kmap_atomic_pte)(struct page *page, enum km_type type);
> -#endif
> -
>  	struct pv_lazy_ops lazy_mode;
>  
>  	/* dom0 ops */
> diff --git a/arch/x86/include/asm/pgtable_32.h b/arch/x86/include/asm/pgtable_32.h
> index 01fd946..b422d22 100644
> --- a/arch/x86/include/asm/pgtable_32.h
> +++ b/arch/x86/include/asm/pgtable_32.h
> @@ -54,10 +54,10 @@ extern void set_pmd_pfn(unsigned long, unsigned long, pgprot_t);
>  	 in_irq() ? KM_IRQ_PTE :	\
>  	 KM_PTE0)
>  #define pte_offset_map(dir, address)					\
> -	((pte_t *)kmap_atomic_pte(pmd_page(*(dir)), __KM_PTE) +		\
> +	((pte_t *)kmap_atomic(pmd_page(*(dir)), __KM_PTE) +		\
>  	 pte_index((address)))
>  #define pte_offset_map_nested(dir, address)				\
> -	((pte_t *)kmap_atomic_pte(pmd_page(*(dir)), KM_PTE1) +		\
> +	((pte_t *)kmap_atomic(pmd_page(*(dir)), KM_PTE1) +		\
>  	 pte_index((address)))
>  #define pte_unmap(pte) kunmap_atomic((pte), __KM_PTE)
>  #define pte_unmap_nested(pte) kunmap_atomic((pte), KM_PTE1)
> diff --git a/arch/x86/kernel/paravirt.c b/arch/x86/kernel/paravirt.c
> index 1b1739d..1db183e 100644
> --- a/arch/x86/kernel/paravirt.c
> +++ b/arch/x86/kernel/paravirt.c
> @@ -428,10 +428,6 @@ struct pv_mmu_ops pv_mmu_ops = {
>  	.ptep_modify_prot_start = __ptep_modify_prot_start,
>  	.ptep_modify_prot_commit = __ptep_modify_prot_commit,
>  
> -#ifdef CONFIG_HIGHPTE
> -	.kmap_atomic_pte = kmap_atomic,
> -#endif
> -
>  #if PAGETABLE_LEVELS >= 3
>  #ifdef CONFIG_X86_PAE
>  	.set_pte_atomic = native_set_pte_atomic,
> diff --git a/arch/x86/kernel/vmi_32.c b/arch/x86/kernel/vmi_32.c
> index 58aca86..7dd599d 100644
> --- a/arch/x86/kernel/vmi_32.c
> +++ b/arch/x86/kernel/vmi_32.c
> @@ -267,22 +267,6 @@ static void vmi_nop(void)
>  {
>  }
>  
> -#ifdef CONFIG_HIGHPTE
> -static void *vmi_kmap_atomic_pte(struct page *page, enum km_type type)
> -{
> -	void *va = kmap_atomic(page, type);
> -
> -	/*
> -	 * We disable highmem allocations for page tables so we should never
> -	 * see any calls to kmap_atomic_pte on a highmem page.
> -	 */
> -
> -	BUG_ON(PageHighmem(page));
> -
> -	return va;
> -}
> -#endif
> -
>  static void vmi_allocate_pte(struct mm_struct *mm, unsigned long pfn)
>  {
>  	vmi_ops.allocate_page(pfn, VMI_PAGE_L1, 0, 0, 0);
> @@ -777,10 +761,6 @@ static inline int __init activate_vmi(void)
>  
>  	/* Set linear is needed in all cases */
>  	vmi_ops.set_linear_mapping = vmi_get_function(VMI_CALL_SetLinearMapping);
> -#ifdef CONFIG_HIGHPTE
> -	if (vmi_ops.set_linear_mapping)
> -		pv_mmu_ops.kmap_atomic_pte = vmi_kmap_atomic_pte;
> -#endif
>  
>  	/*
>  	 * These MUST always be patched.  Don't support indirect jumps
> diff --git a/arch/x86/xen/mmu.c b/arch/x86/xen/mmu.c
> index 350a3de..f9eb7de 100644
> --- a/arch/x86/xen/mmu.c
> +++ b/arch/x86/xen/mmu.c
> @@ -1427,24 +1427,6 @@ static void xen_pgd_free(struct mm_struct *mm, pgd_t *pgd)
>  #endif
>  }
>  
> -#ifdef CONFIG_HIGHPTE
> -static void *xen_kmap_atomic_pte(struct page *page, enum km_type type)
> -{
> -	pgprot_t prot = PAGE_KERNEL;
> -
> -	/*
> -	 * We disable highmem allocations for page tables so we should never
> -	 * see any calls to kmap_atomic_pte on a highmem page.
> -	 */
> -	BUG_ON(PageHighMem(page));
> -
> -	if (PagePinned(page))
> -		prot = PAGE_KERNEL_RO;
> -
> -	return kmap_atomic_prot(page, type, prot);
> -}
> -#endif
> -
>  #ifdef CONFIG_X86_32
>  static __init pte_t mask_rw_pte(pte_t *ptep, pte_t pte)
>  {
> @@ -1903,10 +1885,6 @@ static const struct pv_mmu_ops xen_mmu_ops __initdata = {
>  	.alloc_pmd_clone = paravirt_nop,
>  	.release_pmd = xen_release_pmd_init,
>  
> -#ifdef CONFIG_HIGHPTE
> -	.kmap_atomic_pte = xen_kmap_atomic_pte,
> -#endif
> -
>  #ifdef CONFIG_X86_64
>  	.set_pte = xen_set_pte,
>  #else

Re: [PATCH 2/3] vmi: disable highmem PTE allocation even when CONFIG_HIGHPTE=y

[Alok Kataria]

On Fri, 2010-02-26 at 09:16 -0800, Ian Campbell wrote:
> Preventing HIGHPTE allocations under VMI will allow us to remove the
> kmap_atomic_pte paravirt op.

Acked-by: Alok N Kataria <akataria@vmware.com>

Thanks,
Alok
> 
> Signed-off-by: Ian Campbell <ian.campbell@citrix.com>
> Cc: Alok Kataria <akataria@vmware.com>
> Cc: H. Peter Anvin <hpa@zytor.com>
> Cc: Ingo Molnar <mingo@elte.hu>
> Cc: Jeremy Fitzhardinge <jeremy@goop.org>
> ---
>  arch/x86/kernel/vmi_32.c |   23 +++++++++++------------
>  1 files changed, 11 insertions(+), 12 deletions(-)
> 
> diff --git a/arch/x86/kernel/vmi_32.c b/arch/x86/kernel/vmi_32.c
> index d430e4c..58aca86 100644
> --- a/arch/x86/kernel/vmi_32.c
> +++ b/arch/x86/kernel/vmi_32.c
> @@ -33,6 +33,7 @@
>  #include <asm/fixmap.h>
>  #include <asm/apicdef.h>
>  #include <asm/apic.h>
> +#include <asm/pgalloc.h>
>  #include <asm/processor.h>
>  #include <asm/timer.h>
>  #include <asm/vmi_time.h>
> @@ -272,19 +273,11 @@ static void *vmi_kmap_atomic_pte(struct page *page, enum km_type type)
>  	void *va = kmap_atomic(page, type);
>  
>  	/*
> -	 * Internally, the VMI ROM must map virtual addresses to physical
> -	 * addresses for processing MMU updates.  By the time MMU updates
> -	 * are issued, this information is typically already lost.
> -	 * Fortunately, the VMI provides a cache of mapping slots for active
> -	 * page tables.
> -	 *
> -	 * We use slot zero for the linear mapping of physical memory, and
> -	 * in HIGHPTE kernels, slot 1 and 2 for KM_PTE0 and KM_PTE1.
> -	 *
> -	 *  args:                 SLOT                 VA    COUNT PFN
> +	 * We disable highmem allocations for page tables so we should never
> +	 * see any calls to kmap_atomic_pte on a highmem page.
>  	 */
> -	BUG_ON(type != KM_PTE0 && type != KM_PTE1);
> -	vmi_ops.set_linear_mapping((type - KM_PTE0)+1, va, 1, page_to_pfn(page));
> +
> +	BUG_ON(PageHighmem(page));
>  
>  	return va;
>  }
> @@ -640,6 +633,12 @@ static inline int __init activate_vmi(void)
>  	u64 reloc;
>  	const struct vmi_relocation_info *rel = (struct vmi_relocation_info *)&reloc;
>  
> +	/*
> +	 * Prevent page tables from being allocated in highmem, even if
> +	 * CONFIG_HIGHPTE is enabled.
> +	 */
> +	__userpte_alloc_gfp &= ~__GFP_HIGHMEM;
> +
>  	if (call_vrom_func(vmi_rom, vmi_init) != 0) {
>  		printk(KERN_ERR "VMI ROM failed to initialize!");
>  		return 0;

[tip:x86/mm] x86, vmi: Disable highmem PTE allocation even when CONFIG_HIGHPTE=y

[tip-bot for Ian Campbell]

Commit-ID:  3249b7e1df6380e9d7bb3238f64f445bf614f787
Gitweb:     http://git.kernel.org/tip/3249b7e1df6380e9d7bb3238f64f445bf614f787
Author:     Ian Campbell <ian.campbell@citrix.com>
AuthorDate: Fri, 26 Feb 2010 17:16:01 +0000
Committer:  H. Peter Anvin <hpa@zytor.com>
CommitDate: Sat, 27 Feb 2010 14:41:16 -0800

x86, vmi: Disable highmem PTE allocation even when CONFIG_HIGHPTE=y

Preventing HIGHPTE allocations under VMI will allow us to remove the
kmap_atomic_pte paravirt op.

Signed-off-by: Ian Campbell <ian.campbell@citrix.com>
LKML-Reference: <1267204562-11844-2-git-send-email-ian.campbell@citrix.com>
Acked-by: Alok Kataria <akataria@vmware.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Jeremy Fitzhardinge <jeremy@goop.org>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
---
 arch/x86/kernel/vmi_32.c |   23 +++++++++++------------
 1 files changed, 11 insertions(+), 12 deletions(-)

diff --git a/arch/x86/kernel/vmi_32.c b/arch/x86/kernel/vmi_32.c
index d430e4c..58aca86 100644
--- a/arch/x86/kernel/vmi_32.c
+++ b/arch/x86/kernel/vmi_32.c
@@ -33,6 +33,7 @@
 #include <asm/fixmap.h>
 #include <asm/apicdef.h>
 #include <asm/apic.h>
+#include <asm/pgalloc.h>
 #include <asm/processor.h>
 #include <asm/timer.h>
 #include <asm/vmi_time.h>
@@ -272,19 +273,11 @@ static void *vmi_kmap_atomic_pte(struct page *page, enum km_type type)
 	void *va = kmap_atomic(page, type);
 
 	/*
-	 * Internally, the VMI ROM must map virtual addresses to physical
-	 * addresses for processing MMU updates.  By the time MMU updates
-	 * are issued, this information is typically already lost.
-	 * Fortunately, the VMI provides a cache of mapping slots for active
-	 * page tables.
-	 *
-	 * We use slot zero for the linear mapping of physical memory, and
-	 * in HIGHPTE kernels, slot 1 and 2 for KM_PTE0 and KM_PTE1.
-	 *
-	 *  args:                 SLOT                 VA    COUNT PFN
+	 * We disable highmem allocations for page tables so we should never
+	 * see any calls to kmap_atomic_pte on a highmem page.
 	 */
-	BUG_ON(type != KM_PTE0 && type != KM_PTE1);
-	vmi_ops.set_linear_mapping((type - KM_PTE0)+1, va, 1, page_to_pfn(page));
+
+	BUG_ON(PageHighmem(page));
 
 	return va;
 }
@@ -640,6 +633,12 @@ static inline int __init activate_vmi(void)
 	u64 reloc;
 	const struct vmi_relocation_info *rel = (struct vmi_relocation_info *)&reloc;
 
+	/*
+	 * Prevent page tables from being allocated in highmem, even if
+	 * CONFIG_HIGHPTE is enabled.
+	 */
+	__userpte_alloc_gfp &= ~__GFP_HIGHMEM;
+
 	if (call_vrom_func(vmi_rom, vmi_init) != 0) {
 		printk(KERN_ERR "VMI ROM failed to initialize!");
 		return 0;

[tip:x86/mm] x86, paravirt: Remove kmap_atomic_pte paravirt op.

[tip-bot for Ian Campbell]

Commit-ID:  dad52fc01161afcb8798c609e009aed4d104927f
Gitweb:     http://git.kernel.org/tip/dad52fc01161afcb8798c609e009aed4d104927f
Author:     Ian Campbell <ian.campbell@citrix.com>
AuthorDate: Fri, 26 Feb 2010 17:16:02 +0000
Committer:  H. Peter Anvin <hpa@zytor.com>
CommitDate: Sat, 27 Feb 2010 14:41:35 -0800

x86, paravirt: Remove kmap_atomic_pte paravirt op.

Now that both Xen and VMI disable allocations of PTE pages from high
memory this paravirt op serves no further purpose.

This effectively reverts ce6234b5 "add kmap_atomic_pte for mapping
highpte pages".

Signed-off-by: Ian Campbell <ian.campbell@citrix.com>
LKML-Reference: <1267204562-11844-3-git-send-email-ian.campbell@citrix.com>
Acked-by: Alok Kataria <akataria@vmware.com>
Cc: Jeremy Fitzhardinge <jeremy@goop.org>
Cc: Ingo Molnar <mingo@elte.hu>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
---
 arch/x86/include/asm/highmem.h        |    4 ----
 arch/x86/include/asm/paravirt.h       |    9 ---------
 arch/x86/include/asm/paravirt_types.h |    4 ----
 arch/x86/include/asm/pgtable_32.h     |    4 ++--
 arch/x86/kernel/paravirt.c            |    4 ----
 arch/x86/kernel/vmi_32.c              |   20 --------------------
 arch/x86/xen/mmu.c                    |   22 ----------------------
 7 files changed, 2 insertions(+), 65 deletions(-)

diff --git a/arch/x86/include/asm/highmem.h b/arch/x86/include/asm/highmem.h
index 014c2b8..a726650 100644
--- a/arch/x86/include/asm/highmem.h
+++ b/arch/x86/include/asm/highmem.h
@@ -66,10 +66,6 @@ void *kmap_atomic_pfn(unsigned long pfn, enum km_type type);
 void *kmap_atomic_prot_pfn(unsigned long pfn, enum km_type type, pgprot_t prot);
 struct page *kmap_atomic_to_page(void *ptr);
 
-#ifndef CONFIG_PARAVIRT
-#define kmap_atomic_pte(page, type)	kmap_atomic(page, type)
-#endif
-
 #define flush_cache_kmaps()	do { } while (0)
 
 extern void add_highpages_with_active_regions(int nid, unsigned long start_pfn,
diff --git a/arch/x86/include/asm/paravirt.h b/arch/x86/include/asm/paravirt.h
index dd59a85..5653f43 100644
--- a/arch/x86/include/asm/paravirt.h
+++ b/arch/x86/include/asm/paravirt.h
@@ -435,15 +435,6 @@ static inline void paravirt_release_pud(unsigned long pfn)
 	PVOP_VCALL1(pv_mmu_ops.release_pud, pfn);
 }
 
-#ifdef CONFIG_HIGHPTE
-static inline void *kmap_atomic_pte(struct page *page, enum km_type type)
-{
-	unsigned long ret;
-	ret = PVOP_CALL2(unsigned long, pv_mmu_ops.kmap_atomic_pte, page, type);
-	return (void *)ret;
-}
-#endif
-
 static inline void pte_update(struct mm_struct *mm, unsigned long addr,
 			      pte_t *ptep)
 {
diff --git a/arch/x86/include/asm/paravirt_types.h b/arch/x86/include/asm/paravirt_types.h
index b1e70d5..db9ef55 100644
--- a/arch/x86/include/asm/paravirt_types.h
+++ b/arch/x86/include/asm/paravirt_types.h
@@ -304,10 +304,6 @@ struct pv_mmu_ops {
 #endif	/* PAGETABLE_LEVELS == 4 */
 #endif	/* PAGETABLE_LEVELS >= 3 */
 
-#ifdef CONFIG_HIGHPTE
-	void *(*kmap_atomic_pte)(struct page *page, enum km_type type);
-#endif
-
 	struct pv_lazy_ops lazy_mode;
 
 	/* dom0 ops */
diff --git a/arch/x86/include/asm/pgtable_32.h b/arch/x86/include/asm/pgtable_32.h
index 01fd946..b422d22 100644
--- a/arch/x86/include/asm/pgtable_32.h
+++ b/arch/x86/include/asm/pgtable_32.h
@@ -54,10 +54,10 @@ extern void set_pmd_pfn(unsigned long, unsigned long, pgprot_t);
 	 in_irq() ? KM_IRQ_PTE :	\
 	 KM_PTE0)
 #define pte_offset_map(dir, address)					\
-	((pte_t *)kmap_atomic_pte(pmd_page(*(dir)), __KM_PTE) +		\
+	((pte_t *)kmap_atomic(pmd_page(*(dir)), __KM_PTE) +		\
 	 pte_index((address)))
 #define pte_offset_map_nested(dir, address)				\
-	((pte_t *)kmap_atomic_pte(pmd_page(*(dir)), KM_PTE1) +		\
+	((pte_t *)kmap_atomic(pmd_page(*(dir)), KM_PTE1) +		\
 	 pte_index((address)))
 #define pte_unmap(pte) kunmap_atomic((pte), __KM_PTE)
 #define pte_unmap_nested(pte) kunmap_atomic((pte), KM_PTE1)
diff --git a/arch/x86/kernel/paravirt.c b/arch/x86/kernel/paravirt.c
index 1b1739d..1db183e 100644
--- a/arch/x86/kernel/paravirt.c
+++ b/arch/x86/kernel/paravirt.c
@@ -428,10 +428,6 @@ struct pv_mmu_ops pv_mmu_ops = {
 	.ptep_modify_prot_start = __ptep_modify_prot_start,
 	.ptep_modify_prot_commit = __ptep_modify_prot_commit,
 
-#ifdef CONFIG_HIGHPTE
-	.kmap_atomic_pte = kmap_atomic,
-#endif
-
 #if PAGETABLE_LEVELS >= 3
 #ifdef CONFIG_X86_PAE
 	.set_pte_atomic = native_set_pte_atomic,
diff --git a/arch/x86/kernel/vmi_32.c b/arch/x86/kernel/vmi_32.c
index 58aca86..7dd599d 100644
--- a/arch/x86/kernel/vmi_32.c
+++ b/arch/x86/kernel/vmi_32.c
@@ -267,22 +267,6 @@ static void vmi_nop(void)
 {
 }
 
-#ifdef CONFIG_HIGHPTE
-static void *vmi_kmap_atomic_pte(struct page *page, enum km_type type)
-{
-	void *va = kmap_atomic(page, type);
-
-	/*
-	 * We disable highmem allocations for page tables so we should never
-	 * see any calls to kmap_atomic_pte on a highmem page.
-	 */
-
-	BUG_ON(PageHighmem(page));
-
-	return va;
-}
-#endif
-
 static void vmi_allocate_pte(struct mm_struct *mm, unsigned long pfn)
 {
 	vmi_ops.allocate_page(pfn, VMI_PAGE_L1, 0, 0, 0);
@@ -777,10 +761,6 @@ static inline int __init activate_vmi(void)
 
 	/* Set linear is needed in all cases */
 	vmi_ops.set_linear_mapping = vmi_get_function(VMI_CALL_SetLinearMapping);
-#ifdef CONFIG_HIGHPTE
-	if (vmi_ops.set_linear_mapping)
-		pv_mmu_ops.kmap_atomic_pte = vmi_kmap_atomic_pte;
-#endif
 
 	/*
 	 * These MUST always be patched.  Don't support indirect jumps
diff --git a/arch/x86/xen/mmu.c b/arch/x86/xen/mmu.c
index 350a3de..f9eb7de 100644
--- a/arch/x86/xen/mmu.c
+++ b/arch/x86/xen/mmu.c
@@ -1427,24 +1427,6 @@ static void xen_pgd_free(struct mm_struct *mm, pgd_t *pgd)
 #endif
 }
 
-#ifdef CONFIG_HIGHPTE
-static void *xen_kmap_atomic_pte(struct page *page, enum km_type type)
-{
-	pgprot_t prot = PAGE_KERNEL;
-
-	/*
-	 * We disable highmem allocations for page tables so we should never
-	 * see any calls to kmap_atomic_pte on a highmem page.
-	 */
-	BUG_ON(PageHighMem(page));
-
-	if (PagePinned(page))
-		prot = PAGE_KERNEL_RO;
-
-	return kmap_atomic_prot(page, type, prot);
-}
-#endif
-
 #ifdef CONFIG_X86_32
 static __init pte_t mask_rw_pte(pte_t *ptep, pte_t pte)
 {
@@ -1903,10 +1885,6 @@ static const struct pv_mmu_ops xen_mmu_ops __initdata = {
 	.alloc_pmd_clone = paravirt_nop,
 	.release_pmd = xen_release_pmd_init,
 
-#ifdef CONFIG_HIGHPTE
-	.kmap_atomic_pte = xen_kmap_atomic_pte,
-#endif
-
 #ifdef CONFIG_X86_64
 	.set_pte = xen_set_pte,
 #else