[PATCH v3 0/6] Remove x86-specific code from generic headers

[PATCH v3 0/6] Remove x86-specific code from generic headers

[Thiago Jung Bauermann]

Hello,

This version is mostly about splitting up patch 2/3 into three separate
patches, as suggested by Christoph Hellwig. Two other changes are a fix in
patch 1 which wasn't selecting ARCH_HAS_MEM_ENCRYPT for s390 spotted by
Janani and removal of sme_active and sev_active symbol exports as suggested
by Christoph Hellwig.

These patches are applied on top of today's dma-mapping/for-next.

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

Changelog

Since v2:

- Patch "x86,s390: Move ARCH_HAS_MEM_ENCRYPT definition to arch/Kconfig"
  - Added "select ARCH_HAS_MEM_ENCRYPT" to config S390. Suggested by Janani.

- Patch "DMA mapping: Move SME handling to x86-specific files"
  - Split up into 3 new patches. Suggested by Christoph Hellwig.

- Patch "swiotlb: Remove call to sme_active()"
  - New patch.

- Patch "dma-mapping: Remove dma_check_mask()"
  - New patch.

- Patch "x86,s390/mm: Move sme_active() and sme_me_mask to x86-specific header"
  - New patch.
  - Removed export of sme_active symbol. Suggested by Christoph Hellwig.

- Patch "fs/core/vmcore: Move sev_active() reference to x86 arch code"
  - Removed export of sev_active symbol. Suggested by Christoph Hellwig.

- Patch "s390/mm: Remove sev_active() function"
  - New patch.

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.

Thiago Jung Bauermann (6):
  x86,s390: Move ARCH_HAS_MEM_ENCRYPT definition to arch/Kconfig
  swiotlb: Remove call to sme_active()
  dma-mapping: Remove dma_check_mask()
  x86,s390/mm: Move sme_active() and sme_me_mask to x86-specific header
  fs/core/vmcore: Move sev_active() reference to x86 arch code
  s390/mm: Remove sev_active() function

 arch/Kconfig                        |  3 +++
 arch/s390/Kconfig                   |  4 +---
 arch/s390/include/asm/mem_encrypt.h |  5 +----
 arch/s390/mm/init.c                 |  8 +-------
 arch/x86/Kconfig                    |  4 +---
 arch/x86/include/asm/mem_encrypt.h  | 10 ++++++++++
 arch/x86/kernel/crash_dump_64.c     |  5 +++++
 arch/x86/mm/mem_encrypt.c           |  2 --
 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 +--
 13 files changed, 42 insertions(+), 47 deletions(-)

[PATCH v3 1/6] 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>
Reviewed-by: Christoph Hellwig <hch@lst.de>
---
 arch/Kconfig      | 3 +++
 arch/s390/Kconfig | 4 +---
 arch/x86/Kconfig  | 4 +---
 3 files changed, 5 insertions(+), 6 deletions(-)

diff --git a/arch/Kconfig b/arch/Kconfig
index e8d19c3cb91f..8fc285180848 100644
--- a/arch/Kconfig
+++ b/arch/Kconfig
@@ -935,6 +935,9 @@ 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 a4ad2733eedf..f43319c44454 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
 
@@ -68,6 +65,7 @@ config S390
 	select ARCH_HAS_GCOV_PROFILE_ALL
 	select ARCH_HAS_GIGANTIC_PAGE
 	select ARCH_HAS_KCOV
+	select ARCH_HAS_MEM_ENCRYPT
 	select ARCH_HAS_PTE_SPECIAL
 	select ARCH_HAS_SET_MEMORY
 	select ARCH_HAS_STRICT_KERNEL_RWX
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 v3 2/6] swiotlb: Remove call to sme_active()

[Thiago Jung Bauermann]

sme_active() is an x86-specific function so it's better not to call it from
generic code.

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

Signed-off-by: Thiago Jung Bauermann <bauerman@linux.ibm.com>
---
 kernel/dma/swiotlb.c | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

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 v3 3/6] dma-mapping: Remove dma_check_mask()

[Thiago Jung Bauermann]

sme_active() is an x86-specific function so it's better not to call it from
generic 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 just remove dma_check_mask().

Signed-off-by: Thiago Jung Bauermann <bauerman@linux.ibm.com>
---
 kernel/dma/mapping.c | 8 --------
 1 file changed, 8 deletions(-)

diff --git a/kernel/dma/mapping.c b/kernel/dma/mapping.c
index 1f628e7ac709..61eeefbfcb36 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);
@@ -327,7 +321,6 @@ 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;
 }
@@ -345,7 +338,6 @@ 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;
 }

[PATCH v3 4/6] x86,s390/mm: Move sme_active() and sme_me_mask to x86-specific header

[Thiago Jung Bauermann]

Now that generic code doesn't reference them, move sme_active() and
sme_me_mask to x86's <asm/mem_encrypt.h>.

Also remove the export for sme_active() since it's only used in files that
won't be built as modules. sme_me_mask on the other hand is used in
arch/x86/kvm/svm.c (via __sme_set() and __psp_pa()) which can be built as a
module so its export needs to stay.

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 ++++++++++
 arch/x86/mm/mem_encrypt.c           |  1 -
 include/linux/mem_encrypt.h         | 14 +-------------
 4 files changed, 12 insertions(+), 17 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/arch/x86/mm/mem_encrypt.c b/arch/x86/mm/mem_encrypt.c
index c805f0a5c16e..7139f2f43955 100644
--- a/arch/x86/mm/mem_encrypt.c
+++ b/arch/x86/mm/mem_encrypt.c
@@ -344,7 +344,6 @@ bool sme_active(void)
 {
 	return sme_me_mask && !sev_enabled;
 }
-EXPORT_SYMBOL(sme_active);
 
 bool sev_active(void)
 {
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

[PATCH v3 5/6] 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.

Also, remove the export for sev_active() since it's only used in files that
won't be built as modules.

Signed-off-by: Thiago Jung Bauermann <bauerman@linux.ibm.com>
---
 arch/x86/kernel/crash_dump_64.c |  5 +++++
 arch/x86/mm/mem_encrypt.c       |  1 -
 fs/proc/vmcore.c                |  8 ++++----
 include/linux/crash_dump.h      | 14 ++++++++++++++
 include/linux/mem_encrypt.h     |  1 -
 5 files changed, 23 insertions(+), 6 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/arch/x86/mm/mem_encrypt.c b/arch/x86/mm/mem_encrypt.c
index 7139f2f43955..b1e823441093 100644
--- a/arch/x86/mm/mem_encrypt.c
+++ b/arch/x86/mm/mem_encrypt.c
@@ -349,7 +349,6 @@ bool sev_active(void)
 {
 	return sme_me_mask && sev_enabled;
 }
-EXPORT_SYMBOL(sev_active);
 
 /* Override for DMA direct allocation check - ARCH_HAS_FORCE_DMA_UNENCRYPTED */
 bool force_dma_unencrypted(struct device *dev)
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 */
 

[PATCH v3 6/6] s390/mm: Remove sev_active() function

[Thiago Jung Bauermann]

All references to sev_active() were moved to arch/x86 so we don't need to
define it for s390 anymore.

Signed-off-by: Thiago Jung Bauermann <bauerman@linux.ibm.com>
---
 arch/s390/include/asm/mem_encrypt.h | 1 -
 arch/s390/mm/init.c                 | 8 +-------
 2 files changed, 1 insertion(+), 8 deletions(-)

diff --git a/arch/s390/include/asm/mem_encrypt.h b/arch/s390/include/asm/mem_encrypt.h
index ff813a56bc30..2542cbf7e2d1 100644
--- a/arch/s390/include/asm/mem_encrypt.h
+++ b/arch/s390/include/asm/mem_encrypt.h
@@ -5,7 +5,6 @@
 #ifndef __ASSEMBLY__
 
 static inline bool mem_encrypt_active(void) { return false; }
-extern bool sev_active(void);
 
 int set_memory_encrypted(unsigned long addr, int numpages);
 int set_memory_decrypted(unsigned long addr, int numpages);
diff --git a/arch/s390/mm/init.c b/arch/s390/mm/init.c
index 78c319c5ce48..6286eb3e815b 100644
--- a/arch/s390/mm/init.c
+++ b/arch/s390/mm/init.c
@@ -155,15 +155,9 @@ int set_memory_decrypted(unsigned long addr, int numpages)
 	return 0;
 }
 
-/* are we a protected virtualization guest? */
-bool sev_active(void)
-{
-	return is_prot_virt_guest();
-}
-
 bool force_dma_unencrypted(struct device *dev)
 {
-	return sev_active();
+	return is_prot_virt_guest();
 }
 
 /* protected virtualization */

Re: [PATCH v3 2/6] swiotlb: Remove call to sme_active()

[Christoph Hellwig]

On Thu, Jul 18, 2019 at 12:28:54AM -0300, Thiago Jung Bauermann wrote:
> sme_active() is an x86-specific function so it's better not to call it from
> generic code.
> 
> There's no need to mention which memory encryption feature is active, so
> just use a more generic message. Besides, other architectures will have
> different names for similar technology.
> 
> Signed-off-by: Thiago Jung Bauermann <bauerman@linux.ibm.com>

Looks good,

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

Re: [PATCH v3 3/6] dma-mapping: Remove dma_check_mask()

[Christoph Hellwig]

On Thu, Jul 18, 2019 at 12:28:55AM -0300, Thiago Jung Bauermann wrote:
> sme_active() is an x86-specific function so it's better not to call it from
> generic 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 just remove dma_check_mask().
> 
> Signed-off-by: Thiago Jung Bauermann <bauerman@linux.ibm.com>

Looks good,

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

Re: [PATCH v3 4/6] x86,s390/mm: Move sme_active() and sme_me_mask to x86-specific header

[Christoph Hellwig]

On Thu, Jul 18, 2019 at 12:28:56AM -0300, Thiago Jung Bauermann wrote:
> Now that generic code doesn't reference them, move sme_active() and
> sme_me_mask to x86's <asm/mem_encrypt.h>.
> 
> Also remove the export for sme_active() since it's only used in files that
> won't be built as modules. sme_me_mask on the other hand is used in
> arch/x86/kvm/svm.c (via __sme_set() and __psp_pa()) which can be built as a
> module so its export needs to stay.
> 
> Signed-off-by: Thiago Jung Bauermann <bauerman@linux.ibm.com>

Looks good,

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

Re: [PATCH v3 5/6] fs/core/vmcore: Move sev_active() reference to x86 arch code

[Christoph Hellwig]

On Thu, Jul 18, 2019 at 12:28:57AM -0300, Thiago Jung Bauermann wrote:
> 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.
> 
> Also, remove the export for sev_active() since it's only used in files that
> won't be built as modules.

I have to say I find the __weak overrides of the vmcore files very
confusing and which we'd have a better scheme there.  But as this fits
into that scheme and allows to remove the AMD SME vs SEV knowledge from
the core I'm fine with it.

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

Re: [PATCH v3 6/6] s390/mm: Remove sev_active() function

[Christoph Hellwig]

> -/* are we a protected virtualization guest? */
> -bool sev_active(void)
> -{
> -	return is_prot_virt_guest();
> -}
> -
>  bool force_dma_unencrypted(struct device *dev)
>  {
> -	return sev_active();
> +	return is_prot_virt_guest();
>  }

Do we want to keep the comment for force_dma_unencrypted?

Otherwise looks good:

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

Re: [PATCH v3 6/6] s390/mm: Remove sev_active() function

[Halil Pasic]

On Thu, 18 Jul 2019 10:44:56 +0200
Christoph Hellwig <hch@lst.de> wrote:

> > -/* are we a protected virtualization guest? */
> > -bool sev_active(void)
> > -{
> > -	return is_prot_virt_guest();
> > -}
> > -
> >  bool force_dma_unencrypted(struct device *dev)
> >  {
> > -	return sev_active();
> > +	return is_prot_virt_guest();
> >  }
> 
> Do we want to keep the comment for force_dma_unencrypted?

Yes we do. With the comment transferred:

Reviewed-by: Halil Pasic <pasic@linux.ibm.com>

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

Re: [PATCH v3 6/6] s390/mm: Remove sev_active() function

[Thiago Jung Bauermann]

Christoph Hellwig <hch@lst.de> writes:

>> -/* are we a protected virtualization guest? */
>> -bool sev_active(void)
>> -{
>> -	return is_prot_virt_guest();
>> -}
>> -
>>  bool force_dma_unencrypted(struct device *dev)
>>  {
>> -	return sev_active();
>> +	return is_prot_virt_guest();
>>  }
>
> Do we want to keep the comment for force_dma_unencrypted?
>
> Otherwise looks good:
>
> Reviewed-by: Christoph Hellwig <hch@lst.de>

Thank you for your review on al these patches.

-- 
Thiago Jung Bauermann
IBM Linux Technology Center

Re: [PATCH v3 6/6] s390/mm: Remove sev_active() function

[Thiago Jung Bauermann]

Halil Pasic <pasic@linux.ibm.com> writes:

> On Thu, 18 Jul 2019 10:44:56 +0200
> Christoph Hellwig <hch@lst.de> wrote:
>
>> > -/* are we a protected virtualization guest? */
>> > -bool sev_active(void)
>> > -{
>> > -	return is_prot_virt_guest();
>> > -}
>> > -
>> >  bool force_dma_unencrypted(struct device *dev)
>> >  {
>> > -	return sev_active();
>> > +	return is_prot_virt_guest();
>> >  }
>> 
>> Do we want to keep the comment for force_dma_unencrypted?
>
> Yes we do. With the comment transferred:
>
> Reviewed-by: Halil Pasic <pasic@linux.ibm.com>

Thanks for your review.

Here is the new version. Should I send a new patch series with this
patch and the Reviewed-by on the other ones?

-- 
Thiago Jung Bauermann
IBM Linux Technology Center


From 1726205c73fb9e29feaa3d8909c5a1b0f2054c04 Mon Sep 17 00:00:00 2001
From: Thiago Jung Bauermann <bauerman@linux.ibm.com>
Date: Mon, 15 Jul 2019 20:50:43 -0300
Subject: [PATCH v4] s390/mm: Remove sev_active() function

All references to sev_active() were moved to arch/x86 so we don't need to
define it for s390 anymore.

Signed-off-by: Thiago Jung Bauermann <bauerman@linux.ibm.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Halil Pasic <pasic@linux.ibm.com>
---
 arch/s390/include/asm/mem_encrypt.h | 1 -
 arch/s390/mm/init.c                 | 7 +------
 2 files changed, 1 insertion(+), 7 deletions(-)

diff --git a/arch/s390/include/asm/mem_encrypt.h b/arch/s390/include/asm/mem_encrypt.h
index ff813a56bc30..2542cbf7e2d1 100644
--- a/arch/s390/include/asm/mem_encrypt.h
+++ b/arch/s390/include/asm/mem_encrypt.h
@@ -5,7 +5,6 @@
 #ifndef __ASSEMBLY__
 
 static inline bool mem_encrypt_active(void) { return false; }
-extern bool sev_active(void);
 
 int set_memory_encrypted(unsigned long addr, int numpages);
 int set_memory_decrypted(unsigned long addr, int numpages);
diff --git a/arch/s390/mm/init.c b/arch/s390/mm/init.c
index 78c319c5ce48..6c43a1ed1beb 100644
--- a/arch/s390/mm/init.c
+++ b/arch/s390/mm/init.c
@@ -156,14 +156,9 @@ int set_memory_decrypted(unsigned long addr, int numpages)
 }
 
 /* are we a protected virtualization guest? */
-bool sev_active(void)
-{
-	return is_prot_virt_guest();
-}
-
 bool force_dma_unencrypted(struct device *dev)
 {
-	return sev_active();
+	return is_prot_virt_guest();
 }
 
 /* protected virtualization */

Re: [PATCH v3 2/6] swiotlb: Remove call to sme_active()

[Lendacky, Thomas]

On 7/17/19 10:28 PM, Thiago Jung Bauermann wrote:
> sme_active() is an x86-specific function so it's better not to call it from
> generic code.
> 
> There's no need to mention which memory encryption feature is active, so
> just use a more generic message. Besides, other architectures will have
> different names for similar technology.
> 
> Signed-off-by: Thiago Jung Bauermann <bauerman@linux.ibm.com>

Reviewed-by: Tom Lendacky <thomas.lendacky@amd.com>

> ---
>  kernel/dma/swiotlb.c | 3 +--
>  1 file changed, 1 insertion(+), 2 deletions(-)
> 
> 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);
>  
> 

Re: [PATCH v3 3/6] dma-mapping: Remove dma_check_mask()

[Lendacky, Thomas]

On 7/17/19 10:28 PM, Thiago Jung Bauermann wrote:
> sme_active() is an x86-specific function so it's better not to call it from
> generic 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 just remove dma_check_mask().
> 
> Signed-off-by: Thiago Jung Bauermann <bauerman@linux.ibm.com>

Reviewed-by: Tom Lendacky <thomas.lendacky@amd.com>

> ---
>  kernel/dma/mapping.c | 8 --------
>  1 file changed, 8 deletions(-)
> 
> diff --git a/kernel/dma/mapping.c b/kernel/dma/mapping.c
> index 1f628e7ac709..61eeefbfcb36 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);
> @@ -327,7 +321,6 @@ 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;
>  }
> @@ -345,7 +338,6 @@ 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;
>  }
> 

Re: [PATCH v3 4/6] x86,s390/mm: Move sme_active() and sme_me_mask to x86-specific header

[Lendacky, Thomas]

On 7/17/19 10:28 PM, Thiago Jung Bauermann wrote:
> Now that generic code doesn't reference them, move sme_active() and
> sme_me_mask to x86's <asm/mem_encrypt.h>.
> 
> Also remove the export for sme_active() since it's only used in files that
> won't be built as modules. sme_me_mask on the other hand is used in
> arch/x86/kvm/svm.c (via __sme_set() and __psp_pa()) which can be built as a
> module so its export needs to stay.

You may want to try and build the out-of-tree nvidia driver just to be
sure you can remove the EXPORT_SYMBOL(). But I believe that was related
to the DMA mask check, which now removed, may no longer be a problem.

> 
> Signed-off-by: Thiago Jung Bauermann <bauerman@linux.ibm.com>

Reviewed-by: Tom Lendacky <thomas.lendacky@amd.com>

> ---
>  arch/s390/include/asm/mem_encrypt.h |  4 +---
>  arch/x86/include/asm/mem_encrypt.h  | 10 ++++++++++
>  arch/x86/mm/mem_encrypt.c           |  1 -
>  include/linux/mem_encrypt.h         | 14 +-------------
>  4 files changed, 12 insertions(+), 17 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/arch/x86/mm/mem_encrypt.c b/arch/x86/mm/mem_encrypt.c
> index c805f0a5c16e..7139f2f43955 100644
> --- a/arch/x86/mm/mem_encrypt.c
> +++ b/arch/x86/mm/mem_encrypt.c
> @@ -344,7 +344,6 @@ bool sme_active(void)
>  {
>  	return sme_me_mask && !sev_enabled;
>  }
> -EXPORT_SYMBOL(sme_active);
>  
>  bool sev_active(void)
>  {
> 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
> 

Re: [PATCH v3 5/6] fs/core/vmcore: Move sev_active() reference to x86 arch code

[Lendacky, Thomas]

On 7/17/19 10:28 PM, Thiago Jung Bauermann wrote:
> 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.
> 
> Also, remove the export for sev_active() since it's only used in files that
> won't be built as modules.
> 
> Signed-off-by: Thiago Jung Bauermann <bauerman@linux.ibm.com>

Adding Lianbo and Baoquan, who recently worked on this, for their review.

Thanks,
Tom

> ---
>  arch/x86/kernel/crash_dump_64.c |  5 +++++
>  arch/x86/mm/mem_encrypt.c       |  1 -
>  fs/proc/vmcore.c                |  8 ++++----
>  include/linux/crash_dump.h      | 14 ++++++++++++++
>  include/linux/mem_encrypt.h     |  1 -
>  5 files changed, 23 insertions(+), 6 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/arch/x86/mm/mem_encrypt.c b/arch/x86/mm/mem_encrypt.c
> index 7139f2f43955..b1e823441093 100644
> --- a/arch/x86/mm/mem_encrypt.c
> +++ b/arch/x86/mm/mem_encrypt.c
> @@ -349,7 +349,6 @@ bool sev_active(void)
>  {
>  	return sme_me_mask && sev_enabled;
>  }
> -EXPORT_SYMBOL(sev_active);
>  
>  /* Override for DMA direct allocation check - ARCH_HAS_FORCE_DMA_UNENCRYPTED */
>  bool force_dma_unencrypted(struct device *dev)
> 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 v3 0/6] Remove x86-specific code from generic headers

[Lendacky, Thomas]

On 7/17/19 10:28 PM, Thiago Jung Bauermann wrote:
> Hello,
> 
> This version is mostly about splitting up patch 2/3 into three separate
> patches, as suggested by Christoph Hellwig. Two other changes are a fix in
> patch 1 which wasn't selecting ARCH_HAS_MEM_ENCRYPT for s390 spotted by
> Janani and removal of sme_active and sev_active symbol exports as suggested
> by Christoph Hellwig.
> 
> These patches are applied on top of today's dma-mapping/for-next.
> 
> I don't have a way to test SME, SEV, nor s390's PEF so the patches have only
> been build tested.

I'll try and get this tested quickly to be sure everything works for SME
and SEV.

Thanks,
Tom

> 
> Changelog
> 
> Since v2:
> 
> - Patch "x86,s390: Move ARCH_HAS_MEM_ENCRYPT definition to arch/Kconfig"
>   - Added "select ARCH_HAS_MEM_ENCRYPT" to config S390. Suggested by Janani.
> 
> - Patch "DMA mapping: Move SME handling to x86-specific files"
>   - Split up into 3 new patches. Suggested by Christoph Hellwig.
> 
> - Patch "swiotlb: Remove call to sme_active()"
>   - New patch.
> 
> - Patch "dma-mapping: Remove dma_check_mask()"
>   - New patch.
> 
> - Patch "x86,s390/mm: Move sme_active() and sme_me_mask to x86-specific header"
>   - New patch.
>   - Removed export of sme_active symbol. Suggested by Christoph Hellwig.
> 
> - Patch "fs/core/vmcore: Move sev_active() reference to x86 arch code"
>   - Removed export of sev_active symbol. Suggested by Christoph Hellwig.
> 
> - Patch "s390/mm: Remove sev_active() function"
>   - New patch.
> 
> 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.
> 
> Thiago Jung Bauermann (6):
>   x86,s390: Move ARCH_HAS_MEM_ENCRYPT definition to arch/Kconfig
>   swiotlb: Remove call to sme_active()
>   dma-mapping: Remove dma_check_mask()
>   x86,s390/mm: Move sme_active() and sme_me_mask to x86-specific header
>   fs/core/vmcore: Move sev_active() reference to x86 arch code
>   s390/mm: Remove sev_active() function
> 
>  arch/Kconfig                        |  3 +++
>  arch/s390/Kconfig                   |  4 +---
>  arch/s390/include/asm/mem_encrypt.h |  5 +----
>  arch/s390/mm/init.c                 |  8 +-------
>  arch/x86/Kconfig                    |  4 +---
>  arch/x86/include/asm/mem_encrypt.h  | 10 ++++++++++
>  arch/x86/kernel/crash_dump_64.c     |  5 +++++
>  arch/x86/mm/mem_encrypt.c           |  2 --
>  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 +--
>  13 files changed, 42 insertions(+), 47 deletions(-)
> 

Re: [PATCH v3 4/6] x86,s390/mm: Move sme_active() and sme_me_mask to x86-specific header

[Christoph Hellwig]

On Thu, Jul 18, 2019 at 05:42:18PM +0000, Lendacky, Thomas wrote:
> You may want to try and build the out-of-tree nvidia driver just to be
> sure you can remove the EXPORT_SYMBOL(). But I believe that was related
> to the DMA mask check, which now removed, may no longer be a problem.

Out of tree driver simply don't matter for kernel development decisions.

Re: [PATCH v3 0/6] Remove x86-specific code from generic headers

[Thiago Jung Bauermann]

Lendacky, Thomas <Thomas.Lendacky@amd.com> writes:

> On 7/17/19 10:28 PM, Thiago Jung Bauermann wrote:
>> Hello,
>> 
>> This version is mostly about splitting up patch 2/3 into three separate
>> patches, as suggested by Christoph Hellwig. Two other changes are a fix in
>> patch 1 which wasn't selecting ARCH_HAS_MEM_ENCRYPT for s390 spotted by
>> Janani and removal of sme_active and sev_active symbol exports as suggested
>> by Christoph Hellwig.
>> 
>> These patches are applied on top of today's dma-mapping/for-next.
>> 
>> I don't have a way to test SME, SEV, nor s390's PEF so the patches have only
>> been build tested.
>
> I'll try and get this tested quickly to be sure everything works for SME
> and SEV.

Thanks! And thanks for reviewing the patches.

-- 
Thiago Jung Bauermann
IBM Linux Technology Center

Re: [PATCH v3 5/6] fs/core/vmcore: Move sev_active() reference to x86 arch code

[lijiang]

在 2019年07月19日 01:47, Lendacky, Thomas 写道:
> On 7/17/19 10:28 PM, Thiago Jung Bauermann wrote:
>> 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.
>>
>> Also, remove the export for sev_active() since it's only used in files that
>> won't be built as modules.
>>
>> Signed-off-by: Thiago Jung Bauermann <bauerman@linux.ibm.com>
> 
> Adding Lianbo and Baoquan, who recently worked on this, for their review.
> 

This change looks good to me.

Reviewed-by: Lianbo Jiang <lijiang@redhat.com>

Thanks.
Lianbo

> Thanks,
> Tom
> 
>> ---
>>  arch/x86/kernel/crash_dump_64.c |  5 +++++
>>  arch/x86/mm/mem_encrypt.c       |  1 -
>>  fs/proc/vmcore.c                |  8 ++++----
>>  include/linux/crash_dump.h      | 14 ++++++++++++++
>>  include/linux/mem_encrypt.h     |  1 -
>>  5 files changed, 23 insertions(+), 6 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/arch/x86/mm/mem_encrypt.c b/arch/x86/mm/mem_encrypt.c
>> index 7139f2f43955..b1e823441093 100644
>> --- a/arch/x86/mm/mem_encrypt.c
>> +++ b/arch/x86/mm/mem_encrypt.c
>> @@ -349,7 +349,6 @@ bool sev_active(void)
>>  {
>>  	return sme_me_mask && sev_enabled;
>>  }
>> -EXPORT_SYMBOL(sev_active);
>>  
>>  /* Override for DMA direct allocation check - ARCH_HAS_FORCE_DMA_UNENCRYPTED */
>>  bool force_dma_unencrypted(struct device *dev)
>> 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 v3 0/6] Remove x86-specific code from generic headers

[Lendacky, Thomas]

On 7/18/19 2:44 PM, Thiago Jung Bauermann wrote:
> 
> Lendacky, Thomas <Thomas.Lendacky@amd.com> writes:
> 
>> On 7/17/19 10:28 PM, Thiago Jung Bauermann wrote:
>>> Hello,
>>>
>>> This version is mostly about splitting up patch 2/3 into three separate
>>> patches, as suggested by Christoph Hellwig. Two other changes are a fix in
>>> patch 1 which wasn't selecting ARCH_HAS_MEM_ENCRYPT for s390 spotted by
>>> Janani and removal of sme_active and sev_active symbol exports as suggested
>>> by Christoph Hellwig.
>>>
>>> These patches are applied on top of today's dma-mapping/for-next.
>>>
>>> I don't have a way to test SME, SEV, nor s390's PEF so the patches have only
>>> been build tested.
>>
>> I'll try and get this tested quickly to be sure everything works for SME
>> and SEV.

Built and tested both SME and SEV and everything appears to be working
well (not extensive testing, but should be good enough).

Thanks,
Tom

> 
> Thanks! And thanks for reviewing the patches.
> 

Re: [PATCH v3 0/6] Remove x86-specific code from generic headers

[Thiago Jung Bauermann]

Lendacky, Thomas <Thomas.Lendacky@amd.com> writes:

> On 7/18/19 2:44 PM, Thiago Jung Bauermann wrote:
>> 
>> Lendacky, Thomas <Thomas.Lendacky@amd.com> writes:
>> 
>>> On 7/17/19 10:28 PM, Thiago Jung Bauermann wrote:
>>>> Hello,
>>>>
>>>> This version is mostly about splitting up patch 2/3 into three separate
>>>> patches, as suggested by Christoph Hellwig. Two other changes are a fix in
>>>> patch 1 which wasn't selecting ARCH_HAS_MEM_ENCRYPT for s390 spotted by
>>>> Janani and removal of sme_active and sev_active symbol exports as suggested
>>>> by Christoph Hellwig.
>>>>
>>>> These patches are applied on top of today's dma-mapping/for-next.
>>>>
>>>> I don't have a way to test SME, SEV, nor s390's PEF so the patches have only
>>>> been build tested.
>>>
>>> I'll try and get this tested quickly to be sure everything works for SME
>>> and SEV.
>
> Built and tested both SME and SEV and everything appears to be working
> well (not extensive testing, but should be good enough).

Great news. Thanks for testing!

-- 
Thiago Jung Bauermann
IBM Linux Technology Center

Re: [PATCH v3 5/6] fs/core/vmcore: Move sev_active() reference to x86 arch code

[Thiago Jung Bauermann]

Hello Lianbo,

lijiang <lijiang@redhat.com> writes:

> 在 2019年07月19日 01:47, Lendacky, Thomas 写道:
>> On 7/17/19 10:28 PM, Thiago Jung Bauermann wrote:
>>> 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.
>>>
>>> Also, remove the export for sev_active() since it's only used in files that
>>> won't be built as modules.
>>>
>>> Signed-off-by: Thiago Jung Bauermann <bauerman@linux.ibm.com>
>> 
>> Adding Lianbo and Baoquan, who recently worked on this, for their review.
>> 
>
> This change looks good to me.
>
> Reviewed-by: Lianbo Jiang <lijiang@redhat.com>

Thanks for your review!

-- 
Thiago Jung Bauermann
IBM Linux Technology Center