From: Ma Wupeng <[email protected]>
Commit b05b9f5f9dcf ("x86, mirror: x86 enabling - find mirrored memory ranges")
introduced mirrored memory support for x86. This support rely on UEFI to
report mirrored memory address ranges. See UEFI 2.5 spec pages 157-158:
http://www.uefi.org/sites/default/files/resources/UEFI%202_5.pdf
Memory mirroring is a technique used to separate memory into two separate
channels, usually on a memory device, like a server. In memory mirroring,
one channel is copied to another to create redundancy. This method makes
input/output (I/O) registers and memory appear with more than one address
range because the same physical byte is accessible at more than one
address. Using memory mirroring, higher memory reliability and a higher
level of memory consolidation are possible.
These EFI memory regions have various attributes, and the "mirrored"
attribute is one of them. The physical memory region whose descriptors
in EFI memory map has EFI_MEMORY_MORE_RELIABLE attribute (bit: 16) are
mirrored. The address range mirroring feature of the kernel arranges such
mirrored regions into normal zones and other regions into movable zones.
Arm64 can support this too. So mirrored memory support is added to support
arm64.
The main purpose of this patch set is to introduce mirrored support for
arm64 and we have already fixed the problems we had which is shown in
patch #5 to patch #8 and try to bring total isolation in patch #9 which
will disable mirror feature if kernelcore is not specified.
In order to test this support in arm64:
- patch this patch set
- add kernelcore=mirror in kernel parameter
- start you kernel
Patch #1-#2 introduce mirrored memory support form arm64.
Patch #3-#5 fix some bugs for arm64 if memory reliable is enabled.
Patch #6 disable mirror feature if kernelcore is not specified.
Thanks to Ard Biesheuvel's hard work [1], now kernel will perfer mirrored
memory if kaslr is enabled.
[1] https://lore.kernel.org/linux-arm-kernel/CAMj1kXEPVEzMgOM4+Yj6PxHA-jFuDOAUdDJSiSxy_XaP4P7LSw@mail.gmail.com/T/
Changelog since v2:
- remove efi_fake_mem support
- remove Commit ("remove some redundant code in ia64 efi_init") since
efi_print_memmap() is not public
- add mirror flag back on initrd memory
Changelog since v1:
- update changelog in cover letter
- use PHYS_PFN in patch #7
Ma Wupeng (6):
efi: Make efi_find_mirror() public
arm64/mirror: arm64 enabling - find mirrored memory ranges
mm: Ratelimited mirrored memory related warning messages
mm: Demote warning message in vmemmap_verify() to debug level
mm: Add mirror flag back on initrd memory
efi: Disable mirror feature if kernelcore is not specified
.../admin-guide/kernel-parameters.txt | 2 +-
arch/arm64/kernel/setup.c | 1 +
arch/arm64/mm/init.c | 9 +++++++
arch/x86/include/asm/efi.h | 4 ---
arch/x86/platform/efi/efi.c | 23 ----------------
drivers/firmware/efi/efi.c | 26 +++++++++++++++++++
include/linux/efi.h | 3 +++
include/linux/memblock.h | 1 +
include/linux/mm.h | 2 ++
mm/memblock.c | 24 +++++++++++++++--
mm/page_alloc.c | 2 +-
mm/sparse-vmemmap.c | 2 +-
12 files changed, 67 insertions(+), 32 deletions(-)
--
2.25.1
From: Ma Wupeng <[email protected]>
If system have some mirrored memory and mirrored feature is not specified
in boot parameter, the basic mirrored feature will be enabled and this will
lead to the following situations:
- memblock memory allocation prefers mirrored region. This may have some
unexpected influence on numa affinity.
- contiguous memory will be split into several parts if parts of them
is mirrored memory via memblock_mark_mirror().
To fix this, variable mirrored_kernelcore will be checked before calling
efi_find_mirror() which will enable basic mirrored feature and this
variable is true if kernelcore=mirror is added in the kernel parameters.
Signed-off-by: Ma Wupeng <[email protected]>
---
drivers/firmware/efi/efi.c | 3 +++
include/linux/mm.h | 2 ++
mm/page_alloc.c | 2 +-
3 files changed, 6 insertions(+), 1 deletion(-)
diff --git a/drivers/firmware/efi/efi.c b/drivers/firmware/efi/efi.c
index 79c232e07de7..8a5edcb0dd82 100644
--- a/drivers/firmware/efi/efi.c
+++ b/drivers/firmware/efi/efi.c
@@ -454,6 +454,9 @@ void __init efi_find_mirror(void)
if (!efi_enabled(EFI_MEMMAP))
return;
+ if (!mirrored_kernelcore)
+ return;
+
for_each_efi_memory_desc(md) {
unsigned long long start = md->phys_addr;
unsigned long long size = md->num_pages << EFI_PAGE_SHIFT;
diff --git a/include/linux/mm.h b/include/linux/mm.h
index bc8f326be0ce..741ac7d022c3 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -2540,6 +2540,8 @@ extern void get_pfn_range_for_nid(unsigned int nid,
unsigned long *start_pfn, unsigned long *end_pfn);
extern unsigned long find_min_pfn_with_active_regions(void);
+extern bool mirrored_kernelcore;
+
#ifndef CONFIG_NUMA
static inline int early_pfn_to_nid(unsigned long pfn)
{
diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index e008a3df0485..cf6f70aba787 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -356,7 +356,7 @@ static unsigned long required_kernelcore_percent __initdata;
static unsigned long required_movablecore __initdata;
static unsigned long required_movablecore_percent __initdata;
static unsigned long zone_movable_pfn[MAX_NUMNODES] __initdata;
-static bool mirrored_kernelcore __meminitdata;
+bool mirrored_kernelcore __meminitdata;
/* movable_zone is the "real" zone pages in ZONE_MOVABLE are taken from */
int movable_zone;
--
2.25.1
From: Ma Wupeng <[email protected]>
Commit b05b9f5f9dcf ("x86, mirror: x86 enabling - find mirrored memory
ranges") introduce the efi_find_mirror function on x86. In order to reuse
the API we make it public in preparation for arm64 to support mirrord
memory.
Signed-off-by: Ma Wupeng <[email protected]>
---
arch/x86/include/asm/efi.h | 4 ----
arch/x86/platform/efi/efi.c | 23 -----------------------
drivers/firmware/efi/efi.c | 23 +++++++++++++++++++++++
include/linux/efi.h | 3 +++
4 files changed, 26 insertions(+), 27 deletions(-)
diff --git a/arch/x86/include/asm/efi.h b/arch/x86/include/asm/efi.h
index 71943dce691e..eb90206eae80 100644
--- a/arch/x86/include/asm/efi.h
+++ b/arch/x86/include/asm/efi.h
@@ -383,7 +383,6 @@ static inline bool efi_is_64bit(void)
extern bool efi_reboot_required(void);
extern bool efi_is_table_address(unsigned long phys_addr);
-extern void efi_find_mirror(void);
extern void efi_reserve_boot_services(void);
#else
static inline void parse_efi_setup(u64 phys_addr, u32 data_len) {}
@@ -395,9 +394,6 @@ static inline bool efi_is_table_address(unsigned long phys_addr)
{
return false;
}
-static inline void efi_find_mirror(void)
-{
-}
static inline void efi_reserve_boot_services(void)
{
}
diff --git a/arch/x86/platform/efi/efi.c b/arch/x86/platform/efi/efi.c
index 1591d67e0bcd..6e598bd78eef 100644
--- a/arch/x86/platform/efi/efi.c
+++ b/arch/x86/platform/efi/efi.c
@@ -108,29 +108,6 @@ static int __init setup_add_efi_memmap(char *arg)
}
early_param("add_efi_memmap", setup_add_efi_memmap);
-void __init efi_find_mirror(void)
-{
- efi_memory_desc_t *md;
- u64 mirror_size = 0, total_size = 0;
-
- if (!efi_enabled(EFI_MEMMAP))
- return;
-
- for_each_efi_memory_desc(md) {
- unsigned long long start = md->phys_addr;
- unsigned long long size = md->num_pages << EFI_PAGE_SHIFT;
-
- total_size += size;
- if (md->attribute & EFI_MEMORY_MORE_RELIABLE) {
- memblock_mark_mirror(start, size);
- mirror_size += size;
- }
- }
- if (mirror_size)
- pr_info("Memory: %lldM/%lldM mirrored memory\n",
- mirror_size>>20, total_size>>20);
-}
-
/*
* Tell the kernel about the EFI memory map. This might include
* more than the max 128 entries that can fit in the passed in e820
diff --git a/drivers/firmware/efi/efi.c b/drivers/firmware/efi/efi.c
index 860534bcfdac..79c232e07de7 100644
--- a/drivers/firmware/efi/efi.c
+++ b/drivers/firmware/efi/efi.c
@@ -446,6 +446,29 @@ static int __init efisubsys_init(void)
subsys_initcall(efisubsys_init);
+void __init efi_find_mirror(void)
+{
+ efi_memory_desc_t *md;
+ u64 mirror_size = 0, total_size = 0;
+
+ if (!efi_enabled(EFI_MEMMAP))
+ return;
+
+ for_each_efi_memory_desc(md) {
+ unsigned long long start = md->phys_addr;
+ unsigned long long size = md->num_pages << EFI_PAGE_SHIFT;
+
+ total_size += size;
+ if (md->attribute & EFI_MEMORY_MORE_RELIABLE) {
+ memblock_mark_mirror(start, size);
+ mirror_size += size;
+ }
+ }
+ if (mirror_size)
+ pr_info("Memory: %lldM/%lldM mirrored memory\n",
+ mirror_size>>20, total_size>>20);
+}
+
/*
* Find the efi memory descriptor for a given physical address. Given a
* physical address, determine if it exists within an EFI Memory Map entry,
diff --git a/include/linux/efi.h b/include/linux/efi.h
index 7d9b0bb47eb3..53f64c14a525 100644
--- a/include/linux/efi.h
+++ b/include/linux/efi.h
@@ -872,6 +872,7 @@ static inline bool efi_rt_services_supported(unsigned int mask)
{
return (efi.runtime_supported_mask & mask) == mask;
}
+extern void efi_find_mirror(void);
#else
static inline bool efi_enabled(int feature)
{
@@ -889,6 +890,8 @@ static inline bool efi_rt_services_supported(unsigned int mask)
{
return false;
}
+
+static inline void efi_find_mirror(void) {}
#endif
extern int efi_status_to_err(efi_status_t status);
--
2.25.1
On 2022/6/7 17:38, Wupeng Ma wrote:
> From: Ma Wupeng <[email protected]>
>
> Commit b05b9f5f9dcf ("x86, mirror: x86 enabling - find mirrored memory
> ranges") introduce the efi_find_mirror function on x86. In order to reuse
> the API we make it public in preparation for arm64 to support mirrord
> memory.
Reviewed-by: Kefeng Wang <[email protected]>
> Signed-off-by: Ma Wupeng <[email protected]>
> ---
> arch/x86/include/asm/efi.h | 4 ----
> arch/x86/platform/efi/efi.c | 23 -----------------------
> drivers/firmware/efi/efi.c | 23 +++++++++++++++++++++++
> include/linux/efi.h | 3 +++
> 4 files changed, 26 insertions(+), 27 deletions(-)
>
> diff --git a/arch/x86/include/asm/efi.h b/arch/x86/include/asm/efi.h
> index 71943dce691e..eb90206eae80 100644
> --- a/arch/x86/include/asm/efi.h
> +++ b/arch/x86/include/asm/efi.h
> @@ -383,7 +383,6 @@ static inline bool efi_is_64bit(void)
> extern bool efi_reboot_required(void);
> extern bool efi_is_table_address(unsigned long phys_addr);
>
> -extern void efi_find_mirror(void);
> extern void efi_reserve_boot_services(void);
> #else
> static inline void parse_efi_setup(u64 phys_addr, u32 data_len) {}
> @@ -395,9 +394,6 @@ static inline bool efi_is_table_address(unsigned long phys_addr)
> {
> return false;
> }
> -static inline void efi_find_mirror(void)
> -{
> -}
> static inline void efi_reserve_boot_services(void)
> {
> }
> diff --git a/arch/x86/platform/efi/efi.c b/arch/x86/platform/efi/efi.c
> index 1591d67e0bcd..6e598bd78eef 100644
> --- a/arch/x86/platform/efi/efi.c
> +++ b/arch/x86/platform/efi/efi.c
> @@ -108,29 +108,6 @@ static int __init setup_add_efi_memmap(char *arg)
> }
> early_param("add_efi_memmap", setup_add_efi_memmap);
>
> -void __init efi_find_mirror(void)
> -{
> - efi_memory_desc_t *md;
> - u64 mirror_size = 0, total_size = 0;
> -
> - if (!efi_enabled(EFI_MEMMAP))
> - return;
> -
> - for_each_efi_memory_desc(md) {
> - unsigned long long start = md->phys_addr;
> - unsigned long long size = md->num_pages << EFI_PAGE_SHIFT;
> -
> - total_size += size;
> - if (md->attribute & EFI_MEMORY_MORE_RELIABLE) {
> - memblock_mark_mirror(start, size);
> - mirror_size += size;
> - }
> - }
> - if (mirror_size)
> - pr_info("Memory: %lldM/%lldM mirrored memory\n",
> - mirror_size>>20, total_size>>20);
> -}
> -
> /*
> * Tell the kernel about the EFI memory map. This might include
> * more than the max 128 entries that can fit in the passed in e820
> diff --git a/drivers/firmware/efi/efi.c b/drivers/firmware/efi/efi.c
> index 860534bcfdac..79c232e07de7 100644
> --- a/drivers/firmware/efi/efi.c
> +++ b/drivers/firmware/efi/efi.c
> @@ -446,6 +446,29 @@ static int __init efisubsys_init(void)
>
> subsys_initcall(efisubsys_init);
>
> +void __init efi_find_mirror(void)
> +{
> + efi_memory_desc_t *md;
> + u64 mirror_size = 0, total_size = 0;
> +
> + if (!efi_enabled(EFI_MEMMAP))
> + return;
> +
> + for_each_efi_memory_desc(md) {
> + unsigned long long start = md->phys_addr;
> + unsigned long long size = md->num_pages << EFI_PAGE_SHIFT;
> +
> + total_size += size;
> + if (md->attribute & EFI_MEMORY_MORE_RELIABLE) {
> + memblock_mark_mirror(start, size);
> + mirror_size += size;
> + }
> + }
> + if (mirror_size)
> + pr_info("Memory: %lldM/%lldM mirrored memory\n",
> + mirror_size>>20, total_size>>20);
> +}
> +
> /*
> * Find the efi memory descriptor for a given physical address. Given a
> * physical address, determine if it exists within an EFI Memory Map entry,
> diff --git a/include/linux/efi.h b/include/linux/efi.h
> index 7d9b0bb47eb3..53f64c14a525 100644
> --- a/include/linux/efi.h
> +++ b/include/linux/efi.h
> @@ -872,6 +872,7 @@ static inline bool efi_rt_services_supported(unsigned int mask)
> {
> return (efi.runtime_supported_mask & mask) == mask;
> }
> +extern void efi_find_mirror(void);
> #else
> static inline bool efi_enabled(int feature)
> {
> @@ -889,6 +890,8 @@ static inline bool efi_rt_services_supported(unsigned int mask)
> {
> return false;
> }
> +
> +static inline void efi_find_mirror(void) {}
> #endif
>
> extern int efi_status_to_err(efi_status_t status);
On Fri, 10 Jun 2022 at 13:23, Ard Biesheuvel <[email protected]> wrote:
>
> On Tue, 7 Jun 2022 at 11:16, Wupeng Ma <[email protected]> wrote:
> >
> > From: Ma Wupeng <[email protected]>
> >
> > Commit b05b9f5f9dcf ("x86, mirror: x86 enabling - find mirrored memory ranges")
> > introduced mirrored memory support for x86. This support rely on UEFI to
> > report mirrored memory address ranges. See UEFI 2.5 spec pages 157-158:
> >
> > http://www.uefi.org/sites/default/files/resources/UEFI%202_5.pdf
> >
> > Memory mirroring is a technique used to separate memory into two separate
> > channels, usually on a memory device, like a server. In memory mirroring,
> > one channel is copied to another to create redundancy. This method makes
> > input/output (I/O) registers and memory appear with more than one address
> > range because the same physical byte is accessible at more than one
> > address. Using memory mirroring, higher memory reliability and a higher
> > level of memory consolidation are possible.
> >
> > These EFI memory regions have various attributes, and the "mirrored"
> > attribute is one of them. The physical memory region whose descriptors
> > in EFI memory map has EFI_MEMORY_MORE_RELIABLE attribute (bit: 16) are
> > mirrored. The address range mirroring feature of the kernel arranges such
> > mirrored regions into normal zones and other regions into movable zones.
> >
> > Arm64 can support this too. So mirrored memory support is added to support
> > arm64.
> >
> > The main purpose of this patch set is to introduce mirrored support for
> > arm64 and we have already fixed the problems we had which is shown in
> > patch #5 to patch #8 and try to bring total isolation in patch #9 which
> > will disable mirror feature if kernelcore is not specified.
> >
> > In order to test this support in arm64:
> > - patch this patch set
> > - add kernelcore=mirror in kernel parameter
> > - start you kernel
> >
> > Patch #1-#2 introduce mirrored memory support form arm64.
> > Patch #3-#5 fix some bugs for arm64 if memory reliable is enabled.
> > Patch #6 disable mirror feature if kernelcore is not specified.
> >
> > Thanks to Ard Biesheuvel's hard work [1], now kernel will perfer mirrored
> > memory if kaslr is enabled.
> >
> > [1] https://lore.kernel.org/linux-arm-kernel/CAMj1kXEPVEzMgOM4+Yj6PxHA-jFuDOAUdDJSiSxy_XaP4P7LSw@mail.gmail.com/T/
> >
> > Changelog since v2:
> > - remove efi_fake_mem support
> > - remove Commit ("remove some redundant code in ia64 efi_init") since
> > efi_print_memmap() is not public
> > - add mirror flag back on initrd memory
> >
> > Changelog since v1:
> > - update changelog in cover letter
> > - use PHYS_PFN in patch #7
> >
> > Ma Wupeng (6):
> > efi: Make efi_find_mirror() public
> > arm64/mirror: arm64 enabling - find mirrored memory ranges
> > mm: Ratelimited mirrored memory related warning messages
> > mm: Demote warning message in vmemmap_verify() to debug level
> > mm: Add mirror flag back on initrd memory
> > efi: Disable mirror feature if kernelcore is not specified
> >
>
> I have tested these changes on QEMU/arm64 with the patch below, and
> things seem to work as expected. We have some minor issues to work out
> but the general shape of this code is good.
>
> As for the mm/ changes: does anyone mind if I take those through the
> EFI tree as well? I don't think the EFI and -mm changes depend on each
> other, so they can go into -mm separately as well.
diff --git a/drivers/firmware/efi/libstub/efi-stub.c
b/drivers/firmware/efi/libstub/efi-stub.c
index f515394cce6e..1d4dd8aca3e6 100644
--- a/drivers/firmware/efi/libstub/efi-stub.c
+++ b/drivers/firmware/efi/libstub/efi-stub.c
@@ -136,6 +136,7 @@ efi_status_t __efiapi efi_pe_entry(efi_handle_t handle,
enum efi_secureboot_mode secure_boot;
struct screen_info *si;
efi_properties_table_t *prop_tbl;
+ const efi_dxe_services_table_t *efi_dxe_table;
efi_system_table = sys_table_arg;
@@ -161,6 +162,20 @@ efi_status_t __efiapi efi_pe_entry(efi_handle_t handle,
goto fail;
}
+ efi_dxe_table = get_efi_config_table(EFI_DXE_SERVICES_TABLE_GUID);
+ if (efi_dxe_table) {
+ efi_physical_addr_t pa = 0x60000000;
+ efi_gcd_memory_space_desc_t desc;
+
+ status = efi_dxe_call(get_memory_space_descriptor, pa, &desc);
+ if (status != EFI_SUCCESS)
+ efi_err("Failed to get memory space
descriptor: %lx\n", status);
+ status = efi_dxe_call(set_memory_space_capabilities, pa, SZ_1G,
+ desc.capabilities |
EFI_MEMORY_MORE_RELIABLE);
+ if (status != EFI_SUCCESS)
+ efi_err("Failed to set memory space
capabilities: %lx\n", status);
+ }
+
/*
* Get the command line from EFI, using the LOADED_IMAGE
* protocol. We are going to copy the command line into the
diff --git a/drivers/firmware/efi/libstub/efistub.h
b/drivers/firmware/efi/libstub/efistub.h
index b0ae0a454404..bf11d85bf9b4 100644
--- a/drivers/firmware/efi/libstub/efistub.h
+++ b/drivers/firmware/efi/libstub/efistub.h
@@ -378,7 +378,8 @@ union efi_dxe_services_table {
void *schedule;
void *trust;
void *process_firmware_volume;
- void *set_memory_space_capabilities;
+ efi_status_t (__efiapi
*set_memory_space_capabilities)(efi_physical_addr_t,
+
u64, u64);
};
struct {
efi_table_hdr_t hdr;
On Tue, 7 Jun 2022 at 11:16, Wupeng Ma <[email protected]> wrote:
>
> From: Ma Wupeng <[email protected]>
>
> If system have some mirrored memory and mirrored feature is not specified
> in boot parameter, the basic mirrored feature will be enabled and this will
> lead to the following situations:
>
> - memblock memory allocation prefers mirrored region. This may have some
> unexpected influence on numa affinity.
>
> - contiguous memory will be split into several parts if parts of them
> is mirrored memory via memblock_mark_mirror().
>
> To fix this, variable mirrored_kernelcore will be checked before calling
> efi_find_mirror() which will enable basic mirrored feature and this
> variable is true if kernelcore=mirror is added in the kernel parameters.
>
> Signed-off-by: Ma Wupeng <[email protected]>
This seems like the wrong place to do this. If mirrored memory is
irrelevant to memblock, it should ignore the attribute. So I think
this check belongs in mm/memblock.c instead.
> ---
> drivers/firmware/efi/efi.c | 3 +++
> include/linux/mm.h | 2 ++
> mm/page_alloc.c | 2 +-
> 3 files changed, 6 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/firmware/efi/efi.c b/drivers/firmware/efi/efi.c
> index 79c232e07de7..8a5edcb0dd82 100644
> --- a/drivers/firmware/efi/efi.c
> +++ b/drivers/firmware/efi/efi.c
> @@ -454,6 +454,9 @@ void __init efi_find_mirror(void)
> if (!efi_enabled(EFI_MEMMAP))
> return;
>
> + if (!mirrored_kernelcore)
> + return;
> +
> for_each_efi_memory_desc(md) {
> unsigned long long start = md->phys_addr;
> unsigned long long size = md->num_pages << EFI_PAGE_SHIFT;
> diff --git a/include/linux/mm.h b/include/linux/mm.h
> index bc8f326be0ce..741ac7d022c3 100644
> --- a/include/linux/mm.h
> +++ b/include/linux/mm.h
> @@ -2540,6 +2540,8 @@ extern void get_pfn_range_for_nid(unsigned int nid,
> unsigned long *start_pfn, unsigned long *end_pfn);
> extern unsigned long find_min_pfn_with_active_regions(void);
>
> +extern bool mirrored_kernelcore;
> +
> #ifndef CONFIG_NUMA
> static inline int early_pfn_to_nid(unsigned long pfn)
> {
> diff --git a/mm/page_alloc.c b/mm/page_alloc.c
> index e008a3df0485..cf6f70aba787 100644
> --- a/mm/page_alloc.c
> +++ b/mm/page_alloc.c
> @@ -356,7 +356,7 @@ static unsigned long required_kernelcore_percent __initdata;
> static unsigned long required_movablecore __initdata;
> static unsigned long required_movablecore_percent __initdata;
> static unsigned long zone_movable_pfn[MAX_NUMNODES] __initdata;
> -static bool mirrored_kernelcore __meminitdata;
> +bool mirrored_kernelcore __meminitdata;
>
> /* movable_zone is the "real" zone pages in ZONE_MOVABLE are taken from */
> int movable_zone;
> --
> 2.25.1
>
On Tue, 7 Jun 2022 at 11:16, Wupeng Ma <[email protected]> wrote:
>
> From: Ma Wupeng <[email protected]>
>
> Commit b05b9f5f9dcf ("x86, mirror: x86 enabling - find mirrored memory ranges")
> introduced mirrored memory support for x86. This support rely on UEFI to
> report mirrored memory address ranges. See UEFI 2.5 spec pages 157-158:
>
> http://www.uefi.org/sites/default/files/resources/UEFI%202_5.pdf
>
> Memory mirroring is a technique used to separate memory into two separate
> channels, usually on a memory device, like a server. In memory mirroring,
> one channel is copied to another to create redundancy. This method makes
> input/output (I/O) registers and memory appear with more than one address
> range because the same physical byte is accessible at more than one
> address. Using memory mirroring, higher memory reliability and a higher
> level of memory consolidation are possible.
>
> These EFI memory regions have various attributes, and the "mirrored"
> attribute is one of them. The physical memory region whose descriptors
> in EFI memory map has EFI_MEMORY_MORE_RELIABLE attribute (bit: 16) are
> mirrored. The address range mirroring feature of the kernel arranges such
> mirrored regions into normal zones and other regions into movable zones.
>
> Arm64 can support this too. So mirrored memory support is added to support
> arm64.
>
> The main purpose of this patch set is to introduce mirrored support for
> arm64 and we have already fixed the problems we had which is shown in
> patch #5 to patch #8 and try to bring total isolation in patch #9 which
> will disable mirror feature if kernelcore is not specified.
>
> In order to test this support in arm64:
> - patch this patch set
> - add kernelcore=mirror in kernel parameter
> - start you kernel
>
> Patch #1-#2 introduce mirrored memory support form arm64.
> Patch #3-#5 fix some bugs for arm64 if memory reliable is enabled.
> Patch #6 disable mirror feature if kernelcore is not specified.
>
> Thanks to Ard Biesheuvel's hard work [1], now kernel will perfer mirrored
> memory if kaslr is enabled.
>
> [1] https://lore.kernel.org/linux-arm-kernel/CAMj1kXEPVEzMgOM4+Yj6PxHA-jFuDOAUdDJSiSxy_XaP4P7LSw@mail.gmail.com/T/
>
> Changelog since v2:
> - remove efi_fake_mem support
> - remove Commit ("remove some redundant code in ia64 efi_init") since
> efi_print_memmap() is not public
> - add mirror flag back on initrd memory
>
> Changelog since v1:
> - update changelog in cover letter
> - use PHYS_PFN in patch #7
>
> Ma Wupeng (6):
> efi: Make efi_find_mirror() public
> arm64/mirror: arm64 enabling - find mirrored memory ranges
> mm: Ratelimited mirrored memory related warning messages
> mm: Demote warning message in vmemmap_verify() to debug level
> mm: Add mirror flag back on initrd memory
> efi: Disable mirror feature if kernelcore is not specified
>
I have tested these changes on QEMU/arm64 with the patch below, and
things seem to work as expected. We have some minor issues to work out
but the general shape of this code is good.
As for the mm/ changes: does anyone mind if I take those through the
EFI tree as well? I don't think the EFI and -mm changes depend on each
other, so they can go into -mm separately as well.
On 2022/6/10 19:20, Ard Biesheuvel wrote:
> On Tue, 7 Jun 2022 at 11:16, Wupeng Ma <[email protected]> wrote:
>> From: Ma Wupeng <[email protected]>
>>
>> If system have some mirrored memory and mirrored feature is not specified
>> in boot parameter, the basic mirrored feature will be enabled and this will
>> lead to the following situations:
>>
>> - memblock memory allocation prefers mirrored region. This may have some
>> unexpected influence on numa affinity.
>>
>> - contiguous memory will be split into several parts if parts of them
>> is mirrored memory via memblock_mark_mirror().
>>
>> To fix this, variable mirrored_kernelcore will be checked before calling
>> efi_find_mirror() which will enable basic mirrored feature and this
>> variable is true if kernelcore=mirror is added in the kernel parameters.
>>
>> Signed-off-by: Ma Wupeng <[email protected]>
> This seems like the wrong place to do this. If mirrored memory is
> irrelevant to memblock, it should ignore the attribute. So I think
> this check belongs in mm/memblock.c instead.
Sound good, let's add check into memblock_mark_mirror() and retain
the efi memory mirror information printing.
>
>
>> ---
>> drivers/firmware/efi/efi.c | 3 +++
>> include/linux/mm.h | 2 ++
>> mm/page_alloc.c | 2 +-
>> 3 files changed, 6 insertions(+), 1 deletion(-)
>>
>> diff --git a/drivers/firmware/efi/efi.c b/drivers/firmware/efi/efi.c
>> index 79c232e07de7..8a5edcb0dd82 100644
>> --- a/drivers/firmware/efi/efi.c
>> +++ b/drivers/firmware/efi/efi.c
>> @@ -454,6 +454,9 @@ void __init efi_find_mirror(void)
>> if (!efi_enabled(EFI_MEMMAP))
>> return;
>>
>> + if (!mirrored_kernelcore)
>> + return;
>> +
>> for_each_efi_memory_desc(md) {
>> unsigned long long start = md->phys_addr;
>> unsigned long long size = md->num_pages << EFI_PAGE_SHIFT;
>> diff --git a/include/linux/mm.h b/include/linux/mm.h
>> index bc8f326be0ce..741ac7d022c3 100644
>> --- a/include/linux/mm.h
>> +++ b/include/linux/mm.h
>> @@ -2540,6 +2540,8 @@ extern void get_pfn_range_for_nid(unsigned int nid,
>> unsigned long *start_pfn, unsigned long *end_pfn);
>> extern unsigned long find_min_pfn_with_active_regions(void);
>>
>> +extern bool mirrored_kernelcore;
>> +
>> #ifndef CONFIG_NUMA
>> static inline int early_pfn_to_nid(unsigned long pfn)
>> {
>> diff --git a/mm/page_alloc.c b/mm/page_alloc.c
>> index e008a3df0485..cf6f70aba787 100644
>> --- a/mm/page_alloc.c
>> +++ b/mm/page_alloc.c
>> @@ -356,7 +356,7 @@ static unsigned long required_kernelcore_percent __initdata;
>> static unsigned long required_movablecore __initdata;
>> static unsigned long required_movablecore_percent __initdata;
>> static unsigned long zone_movable_pfn[MAX_NUMNODES] __initdata;
>> -static bool mirrored_kernelcore __meminitdata;
>> +bool mirrored_kernelcore __meminitdata;
>>
>> /* movable_zone is the "real" zone pages in ZONE_MOVABLE are taken from */
>> int movable_zone;
>> --
>> 2.25.1
>>
> .
On Fri, Jun 10, 2022 at 01:23:34PM +0200, Ard Biesheuvel wrote:
> On Tue, 7 Jun 2022 at 11:16, Wupeng Ma <[email protected]> wrote:
> >
> > From: Ma Wupeng <[email protected]>
> >
> > Commit b05b9f5f9dcf ("x86, mirror: x86 enabling - find mirrored memory ranges")
> > introduced mirrored memory support for x86. This support rely on UEFI to
> > report mirrored memory address ranges. See UEFI 2.5 spec pages 157-158:
> >
> > http://www.uefi.org/sites/default/files/resources/UEFI%202_5.pdf
> >
> > Memory mirroring is a technique used to separate memory into two separate
> > channels, usually on a memory device, like a server. In memory mirroring,
> > one channel is copied to another to create redundancy. This method makes
> > input/output (I/O) registers and memory appear with more than one address
> > range because the same physical byte is accessible at more than one
> > address. Using memory mirroring, higher memory reliability and a higher
> > level of memory consolidation are possible.
> >
> > These EFI memory regions have various attributes, and the "mirrored"
> > attribute is one of them. The physical memory region whose descriptors
> > in EFI memory map has EFI_MEMORY_MORE_RELIABLE attribute (bit: 16) are
> > mirrored. The address range mirroring feature of the kernel arranges such
> > mirrored regions into normal zones and other regions into movable zones.
> >
> > Arm64 can support this too. So mirrored memory support is added to support
> > arm64.
> >
> > The main purpose of this patch set is to introduce mirrored support for
> > arm64 and we have already fixed the problems we had which is shown in
> > patch #5 to patch #8 and try to bring total isolation in patch #9 which
> > will disable mirror feature if kernelcore is not specified.
> >
> > In order to test this support in arm64:
> > - patch this patch set
> > - add kernelcore=mirror in kernel parameter
> > - start you kernel
> >
> > Patch #1-#2 introduce mirrored memory support form arm64.
> > Patch #3-#5 fix some bugs for arm64 if memory reliable is enabled.
> > Patch #6 disable mirror feature if kernelcore is not specified.
> >
> > Thanks to Ard Biesheuvel's hard work [1], now kernel will perfer mirrored
> > memory if kaslr is enabled.
> >
> > [1] https://lore.kernel.org/linux-arm-kernel/CAMj1kXEPVEzMgOM4+Yj6PxHA-jFuDOAUdDJSiSxy_XaP4P7LSw@mail.gmail.com/T/
> >
> > Changelog since v2:
> > - remove efi_fake_mem support
> > - remove Commit ("remove some redundant code in ia64 efi_init") since
> > efi_print_memmap() is not public
> > - add mirror flag back on initrd memory
> >
> > Changelog since v1:
> > - update changelog in cover letter
> > - use PHYS_PFN in patch #7
> >
> > Ma Wupeng (6):
> > efi: Make efi_find_mirror() public
> > arm64/mirror: arm64 enabling - find mirrored memory ranges
> > mm: Ratelimited mirrored memory related warning messages
> > mm: Demote warning message in vmemmap_verify() to debug level
> > mm: Add mirror flag back on initrd memory
> > efi: Disable mirror feature if kernelcore is not specified
> >
>
> I have tested these changes on QEMU/arm64 with the patch below, and
> things seem to work as expected. We have some minor issues to work out
> but the general shape of this code is good.
>
> As for the mm/ changes: does anyone mind if I take those through the
> EFI tree as well?
No objections from me.
> I don't think the EFI and -mm changes depend on each other, so they
> can go into -mm separately as well.
--
Sincerely yours,
Mike.