[PATCH v3 0/2] x86: enable SWIOTLB if system has SRAT memory regions above MAX_DMA32_PFN

[PATCH v3 0/2] x86: enable SWIOTLB if system has SRAT memory regions above MAX_DMA32_PFN

[Igor Mammedov]

changes since v2:
  - moved 'max_possible_pfn' tracking hunk to the 1st patch
  - make 'max_possible_pfn' 64-bit
  - simplify condition to oneliner as suggested by Ingo
changes since v1:
  - reduce # of #ifdefs by introducing max_possible_pfn
    global variable
  - don't check 'acpi_no_memhotplug=1' for disabling
    SWIOTLB initialization, since existing 'no_iommu'
    kernel option could be used to the same effect.
  - split into 2 patches
      - 1st adds max_possible_pfn,
      - 2nd fixes bug enabling SWIOTLB when it's needed

when memory hotplug enabled system is booted with less
than 4GB of RAM and then later more RAM is hotplugged
32-bit devices stop functioning with following error:

 nommu_map_single: overflow 327b4f8c0+1522 of device mask ffffffff

the reason for this is that if x86_64 system were booted
with RAM less than 4GB, it doesn't enable SWIOTLB and
when memory is hotplugged beyond MAX_DMA32_PFN, devices
that expect 32-bit addresses can't handle 64-bit addresses.

Fix it by tracking max possible PFN when parsing
memory affinity structures from SRAT ACPI table and
enable SWIOTLB if there is hotpluggable memory
regions beyond MAX_DMA32_PFN.

It fixes KVM guests when they use emulated devices
(reproduces with ata_piix, e1000 and usb devices,
 RHBZ: 1275941, 1275977, 1271527)
It also fixes the HyperV, VMWare with emulated devices
which are affected by this issue as well.

ref to v2:
  https://lkml.org/lkml/2015/12/4/151
ref to v1:
  https://lkml.org/lkml/2015/11/30/594

Igor Mammedov (2):
  x86: introduce max_possible_pfn
  x86_64: enable SWIOTLB if system has SRAT memory regions above
    MAX_DMA32_PFN

 arch/x86/kernel/pci-swiotlb.c | 2 +-
 arch/x86/kernel/setup.c       | 2 ++
 arch/x86/mm/srat.c            | 2 ++
 include/linux/bootmem.h       | 4 ++++
 mm/bootmem.c                  | 1 +
 mm/nobootmem.c                | 1 +
 6 files changed, 11 insertions(+), 1 deletion(-)

-- 
1.8.3.1

[PATCH v3 1/2] x86: introduce max_possible_pfn

[Igor Mammedov]

max_possible_pfn will be used for tracking max possible
PFN for memory that isn't present in E820 table and
could be hotplugged later.

By default max_possible_pfn is initialized with max_pfn,
but later it could be updated with highest PFN of
hotpluggable memory ranges declared in ACPI SRAT table
if any present.

Signed-off-by: Igor Mammedov <imammedo@redhat.com>
---
v3:
 - make 'max_possible_pfn' 64-bit
 - simplify condition to oneliner as suggested by Ingo
---
 arch/x86/kernel/setup.c | 2 ++
 arch/x86/mm/srat.c      | 2 ++
 include/linux/bootmem.h | 4 ++++
 mm/bootmem.c            | 1 +
 mm/nobootmem.c          | 1 +
 5 files changed, 10 insertions(+)

diff --git a/arch/x86/kernel/setup.c b/arch/x86/kernel/setup.c
index 29db25f..16a8465 100644
--- a/arch/x86/kernel/setup.c
+++ b/arch/x86/kernel/setup.c
@@ -1048,6 +1048,8 @@ void __init setup_arch(char **cmdline_p)
 	if (mtrr_trim_uncached_memory(max_pfn))
 		max_pfn = e820_end_of_ram_pfn();
 
+	max_possible_pfn = max_pfn;
+
 #ifdef CONFIG_X86_32
 	/* max_low_pfn get updated here */
 	find_low_pfn_range();
diff --git a/arch/x86/mm/srat.c b/arch/x86/mm/srat.c
index c2aea63..b5f8218 100644
--- a/arch/x86/mm/srat.c
+++ b/arch/x86/mm/srat.c
@@ -203,6 +203,8 @@ acpi_numa_memory_affinity_init(struct acpi_srat_mem_affinity *ma)
 		pr_warn("SRAT: Failed to mark hotplug range [mem %#010Lx-%#010Lx] in memblock\n",
 			(unsigned long long)start, (unsigned long long)end - 1);
 
+	max_possible_pfn = max(max_possible_pfn, PFN_UP(end - 1));
+
 	return 0;
 out_err_bad_srat:
 	bad_srat();
diff --git a/include/linux/bootmem.h b/include/linux/bootmem.h
index f589222..35b22f9 100644
--- a/include/linux/bootmem.h
+++ b/include/linux/bootmem.h
@@ -19,6 +19,10 @@ extern unsigned long min_low_pfn;
  * highest page
  */
 extern unsigned long max_pfn;
+/*
+ * highest possible page
+ */
+extern unsigned long long max_possible_pfn;
 
 #ifndef CONFIG_NO_BOOTMEM
 /*
diff --git a/mm/bootmem.c b/mm/bootmem.c
index 3b63807..91e32bc 100644
--- a/mm/bootmem.c
+++ b/mm/bootmem.c
@@ -33,6 +33,7 @@ EXPORT_SYMBOL(contig_page_data);
 unsigned long max_low_pfn;
 unsigned long min_low_pfn;
 unsigned long max_pfn;
+unsigned long long max_possible_pfn;
 
 bootmem_data_t bootmem_node_data[MAX_NUMNODES] __initdata;
 
diff --git a/mm/nobootmem.c b/mm/nobootmem.c
index e57cf24..99feb2b 100644
--- a/mm/nobootmem.c
+++ b/mm/nobootmem.c
@@ -31,6 +31,7 @@ EXPORT_SYMBOL(contig_page_data);
 unsigned long max_low_pfn;
 unsigned long min_low_pfn;
 unsigned long max_pfn;
+unsigned long long max_possible_pfn;
 
 static void * __init __alloc_memory_core_early(int nid, u64 size, u64 align,
 					u64 goal, u64 limit)
-- 
1.8.3.1

[PATCH v3 2/2] x86_64: enable SWIOTLB if system has SRAT memory regions above MAX_DMA32_PFN

[Igor Mammedov]

when memory hotplug enabled system is booted with less
than 4GB of RAM and then later more RAM is hotplugged
32-bit devices stop functioning with following error:

 nommu_map_single: overflow 327b4f8c0+1522 of device mask ffffffff

the reason for this is that if x86_64 system were booted
with RAM less than 4GB, it doesn't enable SWIOTLB and
when memory is hotplugged beyond MAX_DMA32_PFN, devices
that expect 32-bit addresses can't handle 64-bit addresses.

Fix it by tracking max possible PFN when parsing
memory affinity structures from SRAT ACPI table and
enable SWIOTLB if there is hotpluggable memory
regions beyond MAX_DMA32_PFN.

It fixes KVM guests when they use emulated devices
(reproduces with ata_piix, e1000 and usb devices,
 RHBZ: 1275941, 1275977, 1271527)
It also fixes the HyperV, VMWare with emulated devices
which are affected by this issue as well.

Signed-off-by: Igor Mammedov <imammedo@redhat.com>
---
v3:
 - moved 'max_possible_pfn' tracking hunk to the patch
   that introduces it.
---
 arch/x86/kernel/pci-swiotlb.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/x86/kernel/pci-swiotlb.c b/arch/x86/kernel/pci-swiotlb.c
index adf0392..7c577a1 100644
--- a/arch/x86/kernel/pci-swiotlb.c
+++ b/arch/x86/kernel/pci-swiotlb.c
@@ -88,7 +88,7 @@ int __init pci_swiotlb_detect_4gb(void)
 {
 	/* don't initialize swiotlb if iommu=off (no_iommu=1) */
 #ifdef CONFIG_X86_64
-	if (!no_iommu && max_pfn > MAX_DMA32_PFN)
+	if (!no_iommu && max_possible_pfn > MAX_DMA32_PFN)
 		swiotlb = 1;
 #endif
 	return swiotlb;
-- 
1.8.3.1

[tip:x86/mm] x86/mm: Introduce max_possible_pfn

[tip-bot for Igor Mammedov]

Commit-ID:  8dd3303001976aa8583bf20f6b93590c74114308
Gitweb:     http://git.kernel.org/tip/8dd3303001976aa8583bf20f6b93590c74114308
Author:     Igor Mammedov <imammedo@redhat.com>
AuthorDate: Fri, 4 Dec 2015 14:07:05 +0100
Committer:  Ingo Molnar <mingo@kernel.org>
CommitDate: Sun, 6 Dec 2015 12:46:31 +0100

x86/mm: Introduce max_possible_pfn

max_possible_pfn will be used for tracking max possible
PFN for memory that isn't present in E820 table and
could be hotplugged later.

By default max_possible_pfn is initialized with max_pfn,
but later it could be updated with highest PFN of
hotpluggable memory ranges declared in ACPI SRAT table
if any present.

Signed-off-by: Igor Mammedov <imammedo@redhat.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: akataria@vmware.com
Cc: fujita.tomonori@lab.ntt.co.jp
Cc: konrad.wilk@oracle.com
Cc: pbonzini@redhat.com
Cc: revers@redhat.com
Cc: riel@redhat.com
Link: http://lkml.kernel.org/r/1449234426-273049-2-git-send-email-imammedo@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
---
 arch/x86/kernel/setup.c | 2 ++
 arch/x86/mm/srat.c      | 2 ++
 include/linux/bootmem.h | 4 ++++
 mm/bootmem.c            | 1 +
 mm/nobootmem.c          | 1 +
 5 files changed, 10 insertions(+)

diff --git a/arch/x86/kernel/setup.c b/arch/x86/kernel/setup.c
index 29db25f..16a8465 100644
--- a/arch/x86/kernel/setup.c
+++ b/arch/x86/kernel/setup.c
@@ -1048,6 +1048,8 @@ void __init setup_arch(char **cmdline_p)
 	if (mtrr_trim_uncached_memory(max_pfn))
 		max_pfn = e820_end_of_ram_pfn();
 
+	max_possible_pfn = max_pfn;
+
 #ifdef CONFIG_X86_32
 	/* max_low_pfn get updated here */
 	find_low_pfn_range();
diff --git a/arch/x86/mm/srat.c b/arch/x86/mm/srat.c
index c2aea63..b5f8218 100644
--- a/arch/x86/mm/srat.c
+++ b/arch/x86/mm/srat.c
@@ -203,6 +203,8 @@ acpi_numa_memory_affinity_init(struct acpi_srat_mem_affinity *ma)
 		pr_warn("SRAT: Failed to mark hotplug range [mem %#010Lx-%#010Lx] in memblock\n",
 			(unsigned long long)start, (unsigned long long)end - 1);
 
+	max_possible_pfn = max(max_possible_pfn, PFN_UP(end - 1));
+
 	return 0;
 out_err_bad_srat:
 	bad_srat();
diff --git a/include/linux/bootmem.h b/include/linux/bootmem.h
index f589222..35b22f9 100644
--- a/include/linux/bootmem.h
+++ b/include/linux/bootmem.h
@@ -19,6 +19,10 @@ extern unsigned long min_low_pfn;
  * highest page
  */
 extern unsigned long max_pfn;
+/*
+ * highest possible page
+ */
+extern unsigned long long max_possible_pfn;
 
 #ifndef CONFIG_NO_BOOTMEM
 /*
diff --git a/mm/bootmem.c b/mm/bootmem.c
index 3b63807..91e32bc 100644
--- a/mm/bootmem.c
+++ b/mm/bootmem.c
@@ -33,6 +33,7 @@ EXPORT_SYMBOL(contig_page_data);
 unsigned long max_low_pfn;
 unsigned long min_low_pfn;
 unsigned long max_pfn;
+unsigned long long max_possible_pfn;
 
 bootmem_data_t bootmem_node_data[MAX_NUMNODES] __initdata;
 
diff --git a/mm/nobootmem.c b/mm/nobootmem.c
index e57cf24..99feb2b 100644
--- a/mm/nobootmem.c
+++ b/mm/nobootmem.c
@@ -31,6 +31,7 @@ EXPORT_SYMBOL(contig_page_data);
 unsigned long max_low_pfn;
 unsigned long min_low_pfn;
 unsigned long max_pfn;
+unsigned long long max_possible_pfn;
 
 static void * __init __alloc_memory_core_early(int nid, u64 size, u64 align,
 					u64 goal, u64 limit)

[tip:x86/mm] x86/mm/64: Enable SWIOTLB if system has SRAT memory regions above MAX_DMA32_PFN

[tip-bot for Igor Mammedov]

Commit-ID:  ec941c5ffede4d788b9fc008f9eeca75b9e964f5
Gitweb:     http://git.kernel.org/tip/ec941c5ffede4d788b9fc008f9eeca75b9e964f5
Author:     Igor Mammedov <imammedo@redhat.com>
AuthorDate: Fri, 4 Dec 2015 14:07:06 +0100
Committer:  Ingo Molnar <mingo@kernel.org>
CommitDate: Sun, 6 Dec 2015 12:46:31 +0100

x86/mm/64: Enable SWIOTLB if system has SRAT memory regions above MAX_DMA32_PFN

when memory hotplug enabled system is booted with less
than 4GB of RAM and then later more RAM is hotplugged
32-bit devices stop functioning with following error:

 nommu_map_single: overflow 327b4f8c0+1522 of device mask ffffffff

the reason for this is that if x86_64 system were booted
with RAM less than 4GB, it doesn't enable SWIOTLB and
when memory is hotplugged beyond MAX_DMA32_PFN, devices
that expect 32-bit addresses can't handle 64-bit addresses.

Fix it by tracking max possible PFN when parsing
memory affinity structures from SRAT ACPI table and
enable SWIOTLB if there is hotpluggable memory
regions beyond MAX_DMA32_PFN.

It fixes KVM guests when they use emulated devices
(reproduces with ata_piix, e1000 and usb devices,
 RHBZ: 1275941, 1275977, 1271527)

It also fixes the HyperV, VMWare with emulated devices
which are affected by this issue as well.

Signed-off-by: Igor Mammedov <imammedo@redhat.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: akataria@vmware.com
Cc: fujita.tomonori@lab.ntt.co.jp
Cc: konrad.wilk@oracle.com
Cc: pbonzini@redhat.com
Cc: revers@redhat.com
Cc: riel@redhat.com
Link: http://lkml.kernel.org/r/1449234426-273049-3-git-send-email-imammedo@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
---
 arch/x86/kernel/pci-swiotlb.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/x86/kernel/pci-swiotlb.c b/arch/x86/kernel/pci-swiotlb.c
index adf0392..7c577a1 100644
--- a/arch/x86/kernel/pci-swiotlb.c
+++ b/arch/x86/kernel/pci-swiotlb.c
@@ -88,7 +88,7 @@ int __init pci_swiotlb_detect_4gb(void)
 {
 	/* don't initialize swiotlb if iommu=off (no_iommu=1) */
 #ifdef CONFIG_X86_64
-	if (!no_iommu && max_pfn > MAX_DMA32_PFN)
+	if (!no_iommu && max_possible_pfn > MAX_DMA32_PFN)
 		swiotlb = 1;
 #endif
 	return swiotlb;