[PATCH 2/3] DMA mapping: Move SME handling to x86-specific files

[PATCH 2/3] DMA mapping: Move SME handling to x86-specific files

[Thiago Jung Bauermann]

Secure Memory Encryption is an x86-specific feature, so it shouldn't appear
in generic kernel code.

Introduce ARCH_HAS_DMA_CHECK_MASK so that x86 can define its own
dma_check_mask() for the SME check.

In SWIOTLB code, there's no need to mention which memory encryption
feature is active. Also, other architectures will have different names so
this gets unwieldy quickly.

Signed-off-by: Thiago Jung Bauermann <bauerman@linux.ibm.com>
---
 arch/x86/Kconfig                   |  1 +
 arch/x86/include/asm/dma-mapping.h |  7 +++++++
 arch/x86/include/asm/mem_encrypt.h | 10 ++++++++++
 include/linux/mem_encrypt.h        | 14 +-------------
 kernel/dma/Kconfig                 |  3 +++
 kernel/dma/mapping.c               |  4 ++--
 kernel/dma/swiotlb.c               |  3 +--
 7 files changed, 25 insertions(+), 17 deletions(-)

diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
index 7f4d28da8fe3..dbabe42e7f1c 100644
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -61,6 +61,7 @@ config X86
 	select ARCH_HAS_ACPI_TABLE_UPGRADE	if ACPI
 	select ARCH_HAS_DEBUG_VIRTUAL
 	select ARCH_HAS_DEVMEM_IS_ALLOWED
+	select ARCH_HAS_DMA_CHECK_MASK
 	select ARCH_HAS_ELF_RANDOMIZE
 	select ARCH_HAS_FAST_MULTIPLIER
 	select ARCH_HAS_FILTER_PGPROT
diff --git a/arch/x86/include/asm/dma-mapping.h b/arch/x86/include/asm/dma-mapping.h
index 6b15a24930e0..55e710ba95a5 100644
--- a/arch/x86/include/asm/dma-mapping.h
+++ b/arch/x86/include/asm/dma-mapping.h
@@ -12,6 +12,7 @@
 #include <asm/io.h>
 #include <asm/swiotlb.h>
 #include <linux/dma-contiguous.h>
+#include <linux/mem_encrypt.h>
 
 extern int iommu_merge;
 extern int panic_on_overflow;
@@ -23,4 +24,10 @@ static inline const struct dma_map_ops *get_arch_dma_ops(struct bus_type *bus)
 	return dma_ops;
 }
 
+static inline void dma_check_mask(struct device *dev, u64 mask)
+{
+	if (sme_active() && (mask < (((u64)sme_get_me_mask() << 1) - 1)))
+		dev_warn(dev, "SME is active, device will require DMA bounce buffers\n");
+}
+
 #endif
diff --git a/arch/x86/include/asm/mem_encrypt.h b/arch/x86/include/asm/mem_encrypt.h
index 616f8e637bc3..e4c9e1a57d25 100644
--- a/arch/x86/include/asm/mem_encrypt.h
+++ b/arch/x86/include/asm/mem_encrypt.h
@@ -95,6 +95,16 @@ early_set_memory_encrypted(unsigned long vaddr, unsigned long size) { return 0;
 
 extern char __start_bss_decrypted[], __end_bss_decrypted[], __start_bss_decrypted_unused[];
 
+static inline bool mem_encrypt_active(void)
+{
+	return sme_me_mask;
+}
+
+static inline u64 sme_get_me_mask(void)
+{
+	return sme_me_mask;
+}
+
 #endif	/* __ASSEMBLY__ */
 
 #endif	/* __X86_MEM_ENCRYPT_H__ */
diff --git a/include/linux/mem_encrypt.h b/include/linux/mem_encrypt.h
index b310a9c18113..f2e399fb626b 100644
--- a/include/linux/mem_encrypt.h
+++ b/include/linux/mem_encrypt.h
@@ -21,23 +21,11 @@
 
 #else	/* !CONFIG_ARCH_HAS_MEM_ENCRYPT */
 
-#define sme_me_mask	0ULL
-
-static inline bool sme_active(void) { return false; }
 static inline bool sev_active(void) { return false; }
+static inline bool mem_encrypt_active(void) { return false; }
 
 #endif	/* CONFIG_ARCH_HAS_MEM_ENCRYPT */
 
-static inline bool mem_encrypt_active(void)
-{
-	return sme_me_mask;
-}
-
-static inline u64 sme_get_me_mask(void)
-{
-	return sme_me_mask;
-}
-
 #ifdef CONFIG_AMD_MEM_ENCRYPT
 /*
  * The __sme_set() and __sme_clr() macros are useful for adding or removing
diff --git a/kernel/dma/Kconfig b/kernel/dma/Kconfig
index 9decbba255fc..34b44bfba372 100644
--- a/kernel/dma/Kconfig
+++ b/kernel/dma/Kconfig
@@ -17,6 +17,9 @@ config ARCH_DMA_ADDR_T_64BIT
 config ARCH_HAS_DMA_COHERENCE_H
 	bool
 
+config ARCH_HAS_DMA_CHECK_MASK
+	bool
+
 config ARCH_HAS_DMA_SET_MASK
 	bool
 
diff --git a/kernel/dma/mapping.c b/kernel/dma/mapping.c
index f7afdadb6770..ed46f88378d4 100644
--- a/kernel/dma/mapping.c
+++ b/kernel/dma/mapping.c
@@ -291,11 +291,11 @@ void dma_free_attrs(struct device *dev, size_t size, void *cpu_addr,
 }
 EXPORT_SYMBOL(dma_free_attrs);
 
+#ifndef CONFIG_ARCH_HAS_DMA_CHECK_MASK
 static inline void dma_check_mask(struct device *dev, u64 mask)
 {
-	if (sme_active() && (mask < (((u64)sme_get_me_mask() << 1) - 1)))
-		dev_warn(dev, "SME is active, device will require DMA bounce buffers\n");
 }
+#endif
 
 int dma_supported(struct device *dev, u64 mask)
 {
diff --git a/kernel/dma/swiotlb.c b/kernel/dma/swiotlb.c
index 13f0cb080a4d..67482ad6aab2 100644
--- a/kernel/dma/swiotlb.c
+++ b/kernel/dma/swiotlb.c
@@ -459,8 +459,7 @@ phys_addr_t swiotlb_tbl_map_single(struct device *hwdev,
 		panic("Can not allocate SWIOTLB buffer earlier and can't now provide you with the DMA bounce buffer");
 
 	if (mem_encrypt_active())
-		pr_warn_once("%s is active and system is using DMA bounce buffers\n",
-			     sme_active() ? "SME" : "SEV");
+		pr_warn_once("Memory encryption is active and system is using DMA bounce buffers\n");
 
 	mask = dma_get_seg_boundary(hwdev);
 

Re: [PATCH 2/3] DMA mapping: Move SME handling to x86-specific files

[Christoph Hellwig]

Honestly I think this code should go away without any replacement.
There is no reason why we should have a special debug printk just
for one specific reason why there is a requirement for a large DMA
mask.

Re: [PATCH 2/3] DMA mapping: Move SME handling to x86-specific files

[Thomas Gleixner]

On Fri, 12 Jul 2019, Thiago Jung Bauermann wrote:
> diff --git a/include/linux/mem_encrypt.h b/include/linux/mem_encrypt.h
> index b310a9c18113..f2e399fb626b 100644
> --- a/include/linux/mem_encrypt.h
> +++ b/include/linux/mem_encrypt.h
> @@ -21,23 +21,11 @@
>  
>  #else	/* !CONFIG_ARCH_HAS_MEM_ENCRYPT */
>  
> -#define sme_me_mask	0ULL
> -
> -static inline bool sme_active(void) { return false; }
>  static inline bool sev_active(void) { return false; }

You want to move out sev_active as well, the only relevant thing is
mem_encrypt_active(). Everything SME/SEV is an architecture detail.

> +static inline bool mem_encrypt_active(void) { return false; }

Thanks,

	tglx

Re: [PATCH 2/3] DMA mapping: Move SME handling to x86-specific files

[Thiago Jung Bauermann]

[ Cc'ing Tom Lendacky which I forgot to do earlier. Sorry about that. ]

Hello Christoph,

Christoph Hellwig <hch@lst.de> writes:

> Honestly I think this code should go away without any replacement.
> There is no reason why we should have a special debug printk just
> for one specific reason why there is a requirement for a large DMA
> mask.

Makes sense. I'll submit a v2 which just removes this code.

-- 
Thiago Jung Bauermann
IBM Linux Technology Center

[PATCH 0/3] Remove x86-specific code from generic headers

[Thiago Jung Bauermann]

Hello,

This version mostly changes patch 2/3, removing dma_check_mask() from
kernel/dma/mapping.c as suggested by Christoph Hellwig, and also adapting
s390's <asm/mem_encrypt.h>. There's also a small change in patch 1/3 as
mentioned in the changelog below.

Patch 3/3 may or may not need to change s390 code depending on how Tom
Lendacky's patch is fixed to avoid breaking that architecture, so I haven't
made any changes for now.

These patches are applied on top of today's master which at the time was at
commit 9787aed57dd3 ("coresight: Make the coresight_device_fwnode_match
declaration's fwnode parameter const"), plus a cherry-pick of commit
e67a5ed1f86f ("dma-direct: Force unencrypted DMA under SME for certain DMA
masks"), which is in dma-mapping/for-next and comes from this patch:

https://lore.kernel.org/linux-iommu/10b83d9ff31bca88e94da2ff34e30619eb396078.1562785123.git.thomas.lendacky@amd.com/

I don't have a way to test SME, SEV, nor s390's PEF so the patches have only
been build tested.

Original cover letter below:

Both powerpc¹ and s390² are adding <asm/mem_encrypt.h> headers. Currently,
they have to supply definitions for functions and macros which only have a
meaning on x86: sme_me_mask, sme_active() and sev_active().

Christoph Hellwig made a suggestion to "clean up the Kconfig and generic
headers bits for memory encryption so that we don't need all this
boilerplate code", and this is what this patch does.

After this patch set, this is powerpc's <asm/mem_encrypt.h>:

    #ifndef _ASM_POWERPC_MEM_ENCRYPT_H
    #define _ASM_POWERPC_MEM_ENCRYPT_H

    #include <asm/svm.h>

    static inline bool mem_encrypt_active(void)
    {
	    return is_secure_guest();
    }

    static inline bool force_dma_unencrypted(struct device *dev)
    {
	    return is_secure_guest();
    }

    int set_memory_encrypted(unsigned long addr, int numpages);
    int set_memory_decrypted(unsigned long addr, int numpages);

    #endif /* _ASM_POWERPC_MEM_ENCRYPT_H */

Changelog

Since v1:

- Patch "x86,s390: Move ARCH_HAS_MEM_ENCRYPT definition to arch/Kconfig"
  - Remove definition of ARCH_HAS_MEM_ENCRYPT from s390/Kconfig as well.
  - Reworded patch title and message a little bit.

- Patch "DMA mapping: Move SME handling to x86-specific files"
  - Adapt s390's <asm/mem_encrypt.h> as well.
  - Remove dma_check_mask() from kernel/dma/mapping.c. Suggested by
    Christoph Hellwig.

-- 

¹ https://lore.kernel.org/linuxppc-dev/20190521044912.1375-12-bauerman@linux.ibm.com/
² https://lore.kernel.org/kvm/20190612111236.99538-2-pasic@linux.ibm.com/

Thiago Jung Bauermann (3):
  x86,s390: Move ARCH_HAS_MEM_ENCRYPT definition to arch/Kconfig
  DMA mapping: Move SME handling to x86-specific files
  fs/core/vmcore: Move sev_active() reference to x86 arch code

 arch/Kconfig                        |  3 +++
 arch/s390/Kconfig                   |  3 ---
 arch/s390/include/asm/mem_encrypt.h |  4 +---
 arch/x86/Kconfig                    |  4 +---
 arch/x86/include/asm/mem_encrypt.h  | 10 ++++++++++
 arch/x86/kernel/crash_dump_64.c     |  5 +++++
 fs/proc/vmcore.c                    |  8 ++++----
 include/linux/crash_dump.h          | 14 ++++++++++++++
 include/linux/mem_encrypt.h         | 15 +--------------
 kernel/dma/mapping.c                |  8 --------
 kernel/dma/swiotlb.c                |  3 +--
 11 files changed, 40 insertions(+), 37 deletions(-)

[PATCH 1/3] x86,s390: Move ARCH_HAS_MEM_ENCRYPT definition to arch/Kconfig

[Thiago Jung Bauermann]

powerpc is also going to use this feature, so put it in a generic location.

Signed-off-by: Thiago Jung Bauermann <bauerman@linux.ibm.com>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
---
 arch/Kconfig      | 3 +++
 arch/s390/Kconfig | 3 ---
 arch/x86/Kconfig  | 4 +---
 3 files changed, 4 insertions(+), 6 deletions(-)

diff --git a/arch/Kconfig b/arch/Kconfig
index c47b328eada0..4ef3499d4480 100644
--- a/arch/Kconfig
+++ b/arch/Kconfig
@@ -927,6 +927,9 @@ config LOCK_EVENT_COUNTS
 	  the chance of application behavior change because of timing
 	  differences. The counts are reported via debugfs.
 
+config ARCH_HAS_MEM_ENCRYPT
+	bool
+
 source "kernel/gcov/Kconfig"
 
 source "scripts/gcc-plugins/Kconfig"
diff --git a/arch/s390/Kconfig b/arch/s390/Kconfig
index 5d8570ed6cab..f820e631bf89 100644
--- a/arch/s390/Kconfig
+++ b/arch/s390/Kconfig
@@ -1,7 +1,4 @@
 # SPDX-License-Identifier: GPL-2.0
-config ARCH_HAS_MEM_ENCRYPT
-        def_bool y
-
 config MMU
 	def_bool y
 
diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
index c9f331bb538b..5d3295f2df94 100644
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -68,6 +68,7 @@ config X86
 	select ARCH_HAS_FORTIFY_SOURCE
 	select ARCH_HAS_GCOV_PROFILE_ALL
 	select ARCH_HAS_KCOV			if X86_64
+	select ARCH_HAS_MEM_ENCRYPT
 	select ARCH_HAS_MEMBARRIER_SYNC_CORE
 	select ARCH_HAS_PMEM_API		if X86_64
 	select ARCH_HAS_PTE_SPECIAL
@@ -1520,9 +1521,6 @@ config X86_CPA_STATISTICS
 	  helps to determine the effectiveness of preserving large and huge
 	  page mappings when mapping protections are changed.
 
-config ARCH_HAS_MEM_ENCRYPT
-	def_bool y
-
 config AMD_MEM_ENCRYPT
 	bool "AMD Secure Memory Encryption (SME) support"
 	depends on X86_64 && CPU_SUP_AMD

[PATCH 2/3] DMA mapping: Move SME handling to x86-specific files

[Thiago Jung Bauermann]

Secure Memory Encryption is an x86-specific feature, so it shouldn't appear
in generic kernel code.

In DMA mapping code, Christoph Hellwig mentioned that "There is no reason
why we should have a special debug printk just for one specific reason why
there is a requirement for a large DMA mask.", so we just remove
dma_check_mask().

In SWIOTLB code, there's no need to mention which memory encryption feature
is active, so just use a more generic warning. Besides, other architectures
will have different names for similar technology.

Signed-off-by: Thiago Jung Bauermann <bauerman@linux.ibm.com>
---
 arch/s390/include/asm/mem_encrypt.h |  4 +---
 arch/x86/include/asm/mem_encrypt.h  | 10 ++++++++++
 include/linux/mem_encrypt.h         | 14 +-------------
 kernel/dma/mapping.c                |  8 --------
 kernel/dma/swiotlb.c                |  3 +--
 5 files changed, 13 insertions(+), 26 deletions(-)

diff --git a/arch/s390/include/asm/mem_encrypt.h b/arch/s390/include/asm/mem_encrypt.h
index 3eb018508190..ff813a56bc30 100644
--- a/arch/s390/include/asm/mem_encrypt.h
+++ b/arch/s390/include/asm/mem_encrypt.h
@@ -4,9 +4,7 @@
 
 #ifndef __ASSEMBLY__
 
-#define sme_me_mask	0ULL
-
-static inline bool sme_active(void) { return false; }
+static inline bool mem_encrypt_active(void) { return false; }
 extern bool sev_active(void);
 
 int set_memory_encrypted(unsigned long addr, int numpages);
diff --git a/arch/x86/include/asm/mem_encrypt.h b/arch/x86/include/asm/mem_encrypt.h
index 0c196c47d621..848ce43b9040 100644
--- a/arch/x86/include/asm/mem_encrypt.h
+++ b/arch/x86/include/asm/mem_encrypt.h
@@ -92,6 +92,16 @@ early_set_memory_encrypted(unsigned long vaddr, unsigned long size) { return 0;
 
 extern char __start_bss_decrypted[], __end_bss_decrypted[], __start_bss_decrypted_unused[];
 
+static inline bool mem_encrypt_active(void)
+{
+	return sme_me_mask;
+}
+
+static inline u64 sme_get_me_mask(void)
+{
+	return sme_me_mask;
+}
+
 #endif	/* __ASSEMBLY__ */
 
 #endif	/* __X86_MEM_ENCRYPT_H__ */
diff --git a/include/linux/mem_encrypt.h b/include/linux/mem_encrypt.h
index 470bd53a89df..0c5b0ff9eb29 100644
--- a/include/linux/mem_encrypt.h
+++ b/include/linux/mem_encrypt.h
@@ -18,23 +18,11 @@
 
 #else	/* !CONFIG_ARCH_HAS_MEM_ENCRYPT */
 
-#define sme_me_mask	0ULL
-
-static inline bool sme_active(void) { return false; }
+static inline bool mem_encrypt_active(void) { return false; }
 static inline bool sev_active(void) { return false; }
 
 #endif	/* CONFIG_ARCH_HAS_MEM_ENCRYPT */
 
-static inline bool mem_encrypt_active(void)
-{
-	return sme_me_mask;
-}
-
-static inline u64 sme_get_me_mask(void)
-{
-	return sme_me_mask;
-}
-
 #ifdef CONFIG_AMD_MEM_ENCRYPT
 /*
  * The __sme_set() and __sme_clr() macros are useful for adding or removing
diff --git a/kernel/dma/mapping.c b/kernel/dma/mapping.c
index f7afdadb6770..b53fc7ec4914 100644
--- a/kernel/dma/mapping.c
+++ b/kernel/dma/mapping.c
@@ -291,12 +291,6 @@ void dma_free_attrs(struct device *dev, size_t size, void *cpu_addr,
 }
 EXPORT_SYMBOL(dma_free_attrs);
 
-static inline void dma_check_mask(struct device *dev, u64 mask)
-{
-	if (sme_active() && (mask < (((u64)sme_get_me_mask() << 1) - 1)))
-		dev_warn(dev, "SME is active, device will require DMA bounce buffers\n");
-}
-
 int dma_supported(struct device *dev, u64 mask)
 {
 	const struct dma_map_ops *ops = get_dma_ops(dev);
@@ -321,7 +315,6 @@ int dma_set_mask(struct device *dev, u64 mask)
 		return -EIO;
 
 	arch_dma_set_mask(dev, mask);
-	dma_check_mask(dev, mask);
 	*dev->dma_mask = mask;
 	return 0;
 }
@@ -333,7 +326,6 @@ int dma_set_coherent_mask(struct device *dev, u64 mask)
 	if (!dma_supported(dev, mask))
 		return -EIO;
 
-	dma_check_mask(dev, mask);
 	dev->coherent_dma_mask = mask;
 	return 0;
 }
diff --git a/kernel/dma/swiotlb.c b/kernel/dma/swiotlb.c
index 62fa5a82a065..e52401f94e91 100644
--- a/kernel/dma/swiotlb.c
+++ b/kernel/dma/swiotlb.c
@@ -459,8 +459,7 @@ phys_addr_t swiotlb_tbl_map_single(struct device *hwdev,
 		panic("Can not allocate SWIOTLB buffer earlier and can't now provide you with the DMA bounce buffer");
 
 	if (mem_encrypt_active())
-		pr_warn_once("%s is active and system is using DMA bounce buffers\n",
-			     sme_active() ? "SME" : "SEV");
+		pr_warn_once("Memory encryption is active and system is using DMA bounce buffers\n");
 
 	mask = dma_get_seg_boundary(hwdev);
 

[PATCH 3/3] fs/core/vmcore: Move sev_active() reference to x86 arch code

[Thiago Jung Bauermann]

Secure Encrypted Virtualization is an x86-specific feature, so it shouldn't
appear in generic kernel code because it forces non-x86 architectures to
define the sev_active() function, which doesn't make a lot of sense.

To solve this problem, add an x86 elfcorehdr_read() function to override
the generic weak implementation. To do that, it's necessary to make
read_from_oldmem() public so that it can be used outside of vmcore.c.

Signed-off-by: Thiago Jung Bauermann <bauerman@linux.ibm.com>
---
 arch/x86/kernel/crash_dump_64.c |  5 +++++
 fs/proc/vmcore.c                |  8 ++++----
 include/linux/crash_dump.h      | 14 ++++++++++++++
 include/linux/mem_encrypt.h     |  1 -
 4 files changed, 23 insertions(+), 5 deletions(-)

diff --git a/arch/x86/kernel/crash_dump_64.c b/arch/x86/kernel/crash_dump_64.c
index 22369dd5de3b..045e82e8945b 100644
--- a/arch/x86/kernel/crash_dump_64.c
+++ b/arch/x86/kernel/crash_dump_64.c
@@ -70,3 +70,8 @@ ssize_t copy_oldmem_page_encrypted(unsigned long pfn, char *buf, size_t csize,
 {
 	return __copy_oldmem_page(pfn, buf, csize, offset, userbuf, true);
 }
+
+ssize_t elfcorehdr_read(char *buf, size_t count, u64 *ppos)
+{
+	return read_from_oldmem(buf, count, ppos, 0, sev_active());
+}
diff --git a/fs/proc/vmcore.c b/fs/proc/vmcore.c
index 57957c91c6df..ca1f20bedd8c 100644
--- a/fs/proc/vmcore.c
+++ b/fs/proc/vmcore.c
@@ -100,9 +100,9 @@ static int pfn_is_ram(unsigned long pfn)
 }
 
 /* Reads a page from the oldmem device from given offset. */
-static ssize_t read_from_oldmem(char *buf, size_t count,
-				u64 *ppos, int userbuf,
-				bool encrypted)
+ssize_t read_from_oldmem(char *buf, size_t count,
+			 u64 *ppos, int userbuf,
+			 bool encrypted)
 {
 	unsigned long pfn, offset;
 	size_t nr_bytes;
@@ -166,7 +166,7 @@ void __weak elfcorehdr_free(unsigned long long addr)
  */
 ssize_t __weak elfcorehdr_read(char *buf, size_t count, u64 *ppos)
 {
-	return read_from_oldmem(buf, count, ppos, 0, sev_active());
+	return read_from_oldmem(buf, count, ppos, 0, false);
 }
 
 /*
diff --git a/include/linux/crash_dump.h b/include/linux/crash_dump.h
index f774c5eb9e3c..4664fc1871de 100644
--- a/include/linux/crash_dump.h
+++ b/include/linux/crash_dump.h
@@ -115,4 +115,18 @@ static inline int vmcore_add_device_dump(struct vmcoredd_data *data)
 	return -EOPNOTSUPP;
 }
 #endif /* CONFIG_PROC_VMCORE_DEVICE_DUMP */
+
+#ifdef CONFIG_PROC_VMCORE
+ssize_t read_from_oldmem(char *buf, size_t count,
+			 u64 *ppos, int userbuf,
+			 bool encrypted);
+#else
+static inline ssize_t read_from_oldmem(char *buf, size_t count,
+				       u64 *ppos, int userbuf,
+				       bool encrypted)
+{
+	return -EOPNOTSUPP;
+}
+#endif /* CONFIG_PROC_VMCORE */
+
 #endif /* LINUX_CRASHDUMP_H */
diff --git a/include/linux/mem_encrypt.h b/include/linux/mem_encrypt.h
index 0c5b0ff9eb29..5c4a18a91f89 100644
--- a/include/linux/mem_encrypt.h
+++ b/include/linux/mem_encrypt.h
@@ -19,7 +19,6 @@
 #else	/* !CONFIG_ARCH_HAS_MEM_ENCRYPT */
 
 static inline bool mem_encrypt_active(void) { return false; }
-static inline bool sev_active(void) { return false; }
 
 #endif	/* CONFIG_ARCH_HAS_MEM_ENCRYPT */
 

Re: [PATCH 0/3] Remove x86-specific code from generic headers

[Thiago Jung Bauermann]

I forgot to mark this series as v2 when generating the patches.
Sorry for the confusion.

-- 
Thiago Jung Bauermann
IBM Linux Technology Center

Re: [PATCH 1/3] x86,s390: Move ARCH_HAS_MEM_ENCRYPT definition to arch/Kconfig

[Christoph Hellwig]

On Sat, Jul 13, 2019 at 01:45:52AM -0300, Thiago Jung Bauermann wrote:
> powerpc is also going to use this feature, so put it in a generic location.

Looks good,

even without a third arch using it we should never habe symbols defined
under arch/$(ARCH) that are used in common code to start with.

Reviewed-by: Christoph Hellwig <hch@lst.de>

Re: [PATCH 2/3] DMA mapping: Move SME handling to x86-specific files

[Christoph Hellwig]

While this looks generally good to me, I think we want to split this
into three patches:

 1) update the swiotlb printk
 2) removing the dma-mapping check and printk
 3) clean up the mem_encrypt.h interface.

Re: [PATCH 1/3] x86, s390: Move ARCH_HAS_MEM_ENCRYPT definition to arch/Kconfig

[janani]

On 2019-07-12 23:45, Thiago Jung Bauermann wrote:
> powerpc is also going to use this feature, so put it in a generic 
> location.
> 
> Signed-off-by: Thiago Jung Bauermann <bauerman@linux.ibm.com>
> Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
> ---
>  arch/Kconfig      | 3 +++
>  arch/s390/Kconfig | 3 ---
>  arch/x86/Kconfig  | 4 +---
>  3 files changed, 4 insertions(+), 6 deletions(-)
> 
> diff --git a/arch/Kconfig b/arch/Kconfig
> index c47b328eada0..4ef3499d4480 100644
> --- a/arch/Kconfig
> +++ b/arch/Kconfig
> @@ -927,6 +927,9 @@ config LOCK_EVENT_COUNTS
>  	  the chance of application behavior change because of timing
>  	  differences. The counts are reported via debugfs.
> 
> +config ARCH_HAS_MEM_ENCRYPT
> +	bool
> +
>  source "kernel/gcov/Kconfig"
> 
>  source "scripts/gcc-plugins/Kconfig"
> diff --git a/arch/s390/Kconfig b/arch/s390/Kconfig
> index 5d8570ed6cab..f820e631bf89 100644
> --- a/arch/s390/Kconfig
> +++ b/arch/s390/Kconfig
> @@ -1,7 +1,4 @@
>  # SPDX-License-Identifier: GPL-2.0
> -config ARCH_HAS_MEM_ENCRYPT
> -        def_bool y
> -

  Since you are removing the "def_bool y" when ARCH_HAS_MEM_ENCRYPT is 
moved to arch/Kconfig, does the s390/Kconfig need "select 
ARCH_HAS_MEM_ENCRYPT" added like you do for x86/Kconfig?

  - Janani

>  config MMU
>  	def_bool y
> 
> diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
> index c9f331bb538b..5d3295f2df94 100644
> --- a/arch/x86/Kconfig
> +++ b/arch/x86/Kconfig
> @@ -68,6 +68,7 @@ config X86
>  	select ARCH_HAS_FORTIFY_SOURCE
>  	select ARCH_HAS_GCOV_PROFILE_ALL
>  	select ARCH_HAS_KCOV			if X86_64
> +	select ARCH_HAS_MEM_ENCRYPT
>  	select ARCH_HAS_MEMBARRIER_SYNC_CORE
>  	select ARCH_HAS_PMEM_API		if X86_64
>  	select ARCH_HAS_PTE_SPECIAL
> @@ -1520,9 +1521,6 @@ config X86_CPA_STATISTICS
>  	  helps to determine the effectiveness of preserving large and huge
>  	  page mappings when mapping protections are changed.
> 
> -config ARCH_HAS_MEM_ENCRYPT
> -	def_bool y
> -
>  config AMD_MEM_ENCRYPT
>  	bool "AMD Secure Memory Encryption (SME) support"
>  	depends on X86_64 && CPU_SUP_AMD

Re: [PATCH 1/3] x86, s390: Move ARCH_HAS_MEM_ENCRYPT definition to arch/Kconfig

[Thiago Jung Bauermann]

Hello Janani,

Thanks for reviewing the patch.

janani <janani@linux.ibm.com> writes:

> On 2019-07-12 23:45, Thiago Jung Bauermann wrote:
>> powerpc is also going to use this feature, so put it in a generic location.
>>
>> Signed-off-by: Thiago Jung Bauermann <bauerman@linux.ibm.com>
>> Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
>> ---
>>  arch/Kconfig      | 3 +++
>>  arch/s390/Kconfig | 3 ---
>>  arch/x86/Kconfig  | 4 +---
>>  3 files changed, 4 insertions(+), 6 deletions(-)
>>
>> diff --git a/arch/Kconfig b/arch/Kconfig
>> index c47b328eada0..4ef3499d4480 100644
>> --- a/arch/Kconfig
>> +++ b/arch/Kconfig
>> @@ -927,6 +927,9 @@ config LOCK_EVENT_COUNTS
>>  	  the chance of application behavior change because of timing
>>  	  differences. The counts are reported via debugfs.
>>
>> +config ARCH_HAS_MEM_ENCRYPT
>> +	bool
>> +
>>  source "kernel/gcov/Kconfig"
>>
>>  source "scripts/gcc-plugins/Kconfig"
>> diff --git a/arch/s390/Kconfig b/arch/s390/Kconfig
>> index 5d8570ed6cab..f820e631bf89 100644
>> --- a/arch/s390/Kconfig
>> +++ b/arch/s390/Kconfig
>> @@ -1,7 +1,4 @@
>>  # SPDX-License-Identifier: GPL-2.0
>> -config ARCH_HAS_MEM_ENCRYPT
>> -        def_bool y
>> -
>
>  Since you are removing the "def_bool y" when ARCH_HAS_MEM_ENCRYPT is moved to
> arch/Kconfig, does the s390/Kconfig need "select ARCH_HAS_MEM_ENCRYPT" added
> like you do for x86/Kconfig?

Indeed, I missed that. Thanks for spotting it!

>
>  - Janani
>
>>  config MMU
>>  	def_bool y
>>
>> diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
>> index c9f331bb538b..5d3295f2df94 100644
>> --- a/arch/x86/Kconfig
>> +++ b/arch/x86/Kconfig
>> @@ -68,6 +68,7 @@ config X86
>>  	select ARCH_HAS_FORTIFY_SOURCE
>>  	select ARCH_HAS_GCOV_PROFILE_ALL
>>  	select ARCH_HAS_KCOV			if X86_64
>> +	select ARCH_HAS_MEM_ENCRYPT
>>  	select ARCH_HAS_MEMBARRIER_SYNC_CORE
>>  	select ARCH_HAS_PMEM_API		if X86_64
>>  	select ARCH_HAS_PTE_SPECIAL
>> @@ -1520,9 +1521,6 @@ config X86_CPA_STATISTICS
>>  	  helps to determine the effectiveness of preserving large and huge
>>  	  page mappings when mapping protections are changed.
>>
>> -config ARCH_HAS_MEM_ENCRYPT
>> -	def_bool y
>> -
>>  config AMD_MEM_ENCRYPT
>>  	bool "AMD Secure Memory Encryption (SME) support"
>>  	depends on X86_64 && CPU_SUP_AMD


-- 
Thiago Jung Bauermann
IBM Linux Technology Center

Re: [PATCH 2/3] DMA mapping: Move SME handling to x86-specific files

[Thiago Jung Bauermann]

Thomas Gleixner <tglx@linutronix.de> writes:

> On Fri, 12 Jul 2019, Thiago Jung Bauermann wrote:
>> diff --git a/include/linux/mem_encrypt.h b/include/linux/mem_encrypt.h
>> index b310a9c18113..f2e399fb626b 100644
>> --- a/include/linux/mem_encrypt.h
>> +++ b/include/linux/mem_encrypt.h
>> @@ -21,23 +21,11 @@
>>  
>>  #else	/* !CONFIG_ARCH_HAS_MEM_ENCRYPT */
>>  
>> -#define sme_me_mask	0ULL
>> -
>> -static inline bool sme_active(void) { return false; }
>>  static inline bool sev_active(void) { return false; }
>
> You want to move out sev_active as well, the only relevant thing is
> mem_encrypt_active(). Everything SME/SEV is an architecture detail.

I'm sure you saw it. I addressed sev_active in a separate patch.

Thanks for reviewing this series!

>> +static inline bool mem_encrypt_active(void) { return false; }
>
> Thanks,
>
> 	tglx


-- 
Thiago Jung Bauermann
IBM Linux Technology Center

Re: [PATCH 2/3] DMA mapping: Move SME handling to x86-specific files

[Thiago Jung Bauermann]

kbuild test robot <lkp@intel.com> writes:

> Hi Thiago,
>
> Thank you for the patch! Yet something to improve:
>
> [auto build test ERROR on linus/master]
> [cannot apply to v5.2 next-20190718]
> [if your patch is applied to the wrong git tree, please drop us a note to help improve the system]
>
> url:    https://github.com/0day-ci/linux/commits/Thiago-Jung-Bauermann/Remove-x86-specific-code-from-generic-headers/20190715-063006
> config: s390-allnoconfig (attached as .config)
> compiler: s390-linux-gcc (GCC) 7.4.0
> reproduce:
>         wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
>         chmod +x ~/bin/make.cross
>         # save the attached .config to linux build tree
>         GCC_VERSION=7.4.0 make.cross ARCH=s390
>
> If you fix the issue, kindly add following tag
> Reported-by: kbuild test robot <lkp@intel.com>
>
> All errors (new ones prefixed by >>):
>
>    kernel/dma/swiotlb.c: In function 'swiotlb_tbl_map_single':
>>> kernel/dma/swiotlb.c:461:6: error: implicit declaration of function 'mem_encrypt_active'; did you mean 'set_cpu_active'? [-Werror=implicit-function-declaration]
>      if (mem_encrypt_active())
>          ^~~~~~~~~~~~~~~~~~
>          set_cpu_active
>    cc1: some warnings being treated as errors

This error was reported for v1 of the patch series. I wasn't able to
reproduce this problem on v1 but found a similar issue on v2.

I just did a build test of each patch of the latest version (v3) with an
s390 cross-toolchain and the config file from this report and didn't
find any build issues, so I believe this problem is solved.

--
Thiago Jung Bauermann
IBM Linux Technology Center