[PATCH 1/1] s390/protvirt: restore force_dma_unencrypted()

[Halil Pasic <pasic@linux.ibm.com>]

Since commit e67a5ed1f86f ("dma-direct: Force unencrypted DMA under SME
for certain DMA masks"), force_dma_unencrypted() is broken on s390
(under protvirt). Before used to return sev_active(), after it became
practically architecture specific, with the default implementation
always returning false.

Let's restore the old behavior of force_dma_unencrypted().

Note: we still need sev_active() defined because of the reference
in fs/core/vmcore, but this one is likely to go away soon along
with the need for an s390 sev_active().

Signed-off-by: Halil Pasic <pasic@linux.ibm.com>
Fixes: e67a5ed1f86f ("dma-direct: Force unencrypted DMA under SME for
certain DMA masks")

--

Thiago has a path that gets rid of the fs/core/vmcore reference. Link:
https://patchwork.ozlabs.org/patch/1131571/

Prior discussion:
https://www.spinics.net/lists/kernel/msg3189113.html
---
 arch/s390/Kconfig                   | 1 +
 arch/s390/include/asm/mem_encrypt.h | 2 +-
 arch/s390/mm/init.c                 | 2 +-
 3 files changed, 3 insertions(+), 2 deletions(-)

diff --git a/arch/s390/Kconfig b/arch/s390/Kconfig
index 5d8570ed6cab..a4ad2733eedf 100644
--- a/arch/s390/Kconfig
+++ b/arch/s390/Kconfig
@@ -189,6 +189,7 @@ config S390
 	select VIRT_CPU_ACCOUNTING
 	select ARCH_HAS_SCALED_CPUTIME
 	select HAVE_NMI
+	select ARCH_HAS_FORCE_DMA_UNENCRYPTED
 	select SWIOTLB
 	select GENERIC_ALLOCATOR
 
diff --git a/arch/s390/include/asm/mem_encrypt.h b/arch/s390/include/asm/mem_encrypt.h
index 3eb018508190..f8453f8cc191 100644
--- a/arch/s390/include/asm/mem_encrypt.h
+++ b/arch/s390/include/asm/mem_encrypt.h
@@ -7,7 +7,7 @@
 #define sme_me_mask	0ULL
 
 static inline bool sme_active(void) { return false; }
-extern bool sev_active(void);
+static inline bool sev_active(void) { return false; }
 
 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 f0bee6af3960..023ab4221687 100644
--- a/arch/s390/mm/init.c
+++ b/arch/s390/mm/init.c
@@ -156,7 +156,7 @@ int set_memory_decrypted(unsigned long addr, int numpages)
 }
 
 /* are we a protected virtualization guest? */
-bool sev_active(void)
+bool force_dma_unencrypted(struct device *dev)
 {
 	return is_prot_virt_guest();
 }
-- 
2.17.1