arm64/coco: Add pKVM as a CC platform

pKVM does support memory encryption, expose that to the rest of
the kernel through cc_platform_has()

At the moment, all devices inside the guest are emulated which
requires its memory to be shared back to the host (decrypted), so
set force_dma_unencrypted() to always return true.

Although, typically pKVM guests rely on restricted-dma-pools to
bounce traffic, with this change, it is possible to solely rely on
the default SWIOTLB for that (assuming the appropriate size is set
from the command line)

Signed-off-by: Mostafa Saleh <smostafa@google.com>
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Tested-by: Aneesh Kumar K.V (Arm) <aneesh.kumar@kernel.org>
Signed-off-by: Will Deacon <will@kernel.org>

1 files changed, 0 insertions, 12 deletions

diff --git a/arch/arm64/kernel/rsi.c b/arch/arm64/kernel/rsi.c
index 92160f2e57ff..25ca75ce1a4d 100644
--- a/arch/arm64/kernel/rsi.c
+++ b/arch/arm64/kernel/rsi.c
@@ -7,7 +7,6 @@
 #include <linux/memblock.h>
 #include <linux/psci.h>
 #include <linux/swiotlb.h>
-#include <linux/cc_platform.h>
 #include <linux/platform_device.h>
 
 #include <asm/io.h>
@@ -23,17 +22,6 @@ EXPORT_SYMBOL(prot_ns_shared);
 DEFINE_STATIC_KEY_FALSE_RO(rsi_present);
 EXPORT_SYMBOL(rsi_present);
 
-bool cc_platform_has(enum cc_attr attr)
-{
-	switch (attr) {
-	case CC_ATTR_MEM_ENCRYPT:
-		return is_realm_world();
-	default:
-		return false;
-	}
-}
-EXPORT_SYMBOL_GPL(cc_platform_has);
-
 static bool rsi_version_matches(void)
 {
 	unsigned long ver_lower, ver_higher;