Protected virtualization guests use memory encryption, so advertise that to
the rest of the kernel through cc_platform_has(CC_ATTR_MEM_ENCRYPT).

s390 already forces DMA mappings to be unencrypted for protected
virtualization guests through force_dma_unencrypted(). Add
ARCH_HAS_CC_PLATFORM and provide the matching cc_platform_has()
implementation

Signed-off-by: Aneesh Kumar K.V (Arm) <[email protected]>
---
Cc: Halil Pasic <[email protected]>
Cc: Matthew Rosato <[email protected]>
Cc: Jaehoon  Kim <[email protected]>
---
 arch/s390/Kconfig   |  1 +
 arch/s390/mm/init.c | 14 ++++++++++++++
 2 files changed, 15 insertions(+)

diff --git a/arch/s390/Kconfig b/arch/s390/Kconfig
index ecbcbb781e40..9b5e6029e043 100644
--- a/arch/s390/Kconfig
+++ b/arch/s390/Kconfig
@@ -87,6 +87,7 @@ config S390
        select ARCH_ENABLE_SPLIT_PMD_PTLOCK if PGTABLE_LEVELS > 2
        select ARCH_ENABLE_THP_MIGRATION if TRANSPARENT_HUGEPAGE
        select ARCH_HAS_CC_CAN_LINK
+       select ARCH_HAS_CC_PLATFORM
        select ARCH_HAS_CPU_FINALIZE_INIT
        select ARCH_HAS_CURRENT_STACK_POINTER
        select ARCH_HAS_DEBUG_VIRTUAL
diff --git a/arch/s390/mm/init.c b/arch/s390/mm/init.c
index 1f72efc2a579..ad3c6d92b801 100644
--- a/arch/s390/mm/init.c
+++ b/arch/s390/mm/init.c
@@ -50,6 +50,7 @@
 #include <linux/virtio_anchor.h>
 #include <linux/virtio_config.h>
 #include <linux/execmem.h>
+#include <linux/cc_platform.h>
 
 pgd_t swapper_pg_dir[PTRS_PER_PGD] __section(".bss..swapper_pg_dir");
 pgd_t invalid_pg_dir[PTRS_PER_PGD] __section(".bss..invalid_pg_dir");
@@ -140,6 +141,19 @@ bool force_dma_unencrypted(struct device *dev)
        return is_prot_virt_guest();
 }
 
+
+bool cc_platform_has(enum cc_attr attr)
+{
+       switch (attr) {
+       case CC_ATTR_MEM_ENCRYPT:
+               return is_prot_virt_guest();
+
+       default:
+               return false;
+       }
+}
+EXPORT_SYMBOL_GPL(cc_platform_has);
+
 /* protected virtualization */
 static void __init pv_init(void)
 {
-- 
2.43.0


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