[PATCH v5 01/20] [DO NOT MERGE] arm64/coco: Add pKVM as a CC platform

[Aneesh Kumar K.V (Arm)]

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.

Signed-off-by: Mostafa Saleh <smostafa at google.com>
Signed-off-by: Aneesh Kumar K.V (Arm) <aneesh.kumar at kernel.org>
---
 arch/arm64/include/asm/hypervisor.h           |  6 ++++++
 arch/arm64/include/asm/mem_encrypt.h          |  3 ++-
 arch/arm64/kernel/rsi.c                       | 12 ------------
 arch/arm64/mm/init.c                          | 13 +++++++++++++
 drivers/virt/coco/pkvm-guest/arm-pkvm-guest.c |  5 +++++
 5 files changed, 26 insertions(+), 13 deletions(-)

diff --git a/arch/arm64/include/asm/hypervisor.h b/arch/arm64/include/asm/hypervisor.h
index a12fd897c877..1b0e15f290be 100644
--- a/arch/arm64/include/asm/hypervisor.h
+++ b/arch/arm64/include/asm/hypervisor.h
@@ -10,8 +10,14 @@ void kvm_arm_target_impl_cpu_init(void);
 
 #ifdef CONFIG_ARM_PKVM_GUEST
 void pkvm_init_hyp_services(void);
+bool is_protected_kvm_guest(void);
 #else
 static inline void pkvm_init_hyp_services(void) { };
+
+static inline bool is_protected_kvm_guest(void)
+{
+	return false;
+}
 #endif
 
 static inline void kvm_arch_init_hyp_services(void)
diff --git a/arch/arm64/include/asm/mem_encrypt.h b/arch/arm64/include/asm/mem_encrypt.h
index 314b2b52025f..636f45b4d8af 100644
--- a/arch/arm64/include/asm/mem_encrypt.h
+++ b/arch/arm64/include/asm/mem_encrypt.h
@@ -2,6 +2,7 @@
 #ifndef __ASM_MEM_ENCRYPT_H
 #define __ASM_MEM_ENCRYPT_H
 
+#include <asm/hypervisor.h>
 #include <asm/rsi.h>
 
 struct device;
@@ -20,7 +21,7 @@ int realm_register_memory_enc_ops(void);
 
 static inline bool force_dma_unencrypted(struct device *dev)
 {
-	return is_realm_world();
+	return is_realm_world() || is_protected_kvm_guest();
 }
 
 /*
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;
diff --git a/arch/arm64/mm/init.c b/arch/arm64/mm/init.c
index 97987f850a33..c1b223e7cc8e 100644
--- a/arch/arm64/mm/init.c
+++ b/arch/arm64/mm/init.c
@@ -12,6 +12,7 @@
 #include <linux/swap.h>
 #include <linux/init.h>
 #include <linux/cache.h>
+#include <linux/cc_platform.h>
 #include <linux/mman.h>
 #include <linux/nodemask.h>
 #include <linux/initrd.h>
@@ -36,6 +37,7 @@
 
 #include <asm/boot.h>
 #include <asm/fixmap.h>
+#include <asm/hypervisor.h>
 #include <asm/kasan.h>
 #include <asm/kernel-pgtable.h>
 #include <asm/kvm_host.h>
@@ -416,6 +418,17 @@ void dump_mem_limit(void)
 	}
 }
 
+bool cc_platform_has(enum cc_attr attr)
+{
+	switch (attr) {
+	case CC_ATTR_MEM_ENCRYPT:
+		return is_realm_world() || is_protected_kvm_guest();
+	default:
+		return false;
+	}
+}
+EXPORT_SYMBOL_GPL(cc_platform_has);
+
 #ifdef CONFIG_EXECMEM
 static u64 module_direct_base __ro_after_init = 0;
 static u64 module_plt_base __ro_after_init = 0;
diff --git a/drivers/virt/coco/pkvm-guest/arm-pkvm-guest.c b/drivers/virt/coco/pkvm-guest/arm-pkvm-guest.c
index 4230b817a80b..297e6d6019b8 100644
--- a/drivers/virt/coco/pkvm-guest/arm-pkvm-guest.c
+++ b/drivers/virt/coco/pkvm-guest/arm-pkvm-guest.c
@@ -95,6 +95,11 @@ static int mmio_guard_ioremap_hook(phys_addr_t phys, size_t size,
 	return 0;
 }
 
+bool is_protected_kvm_guest(void)
+{
+	return !!pkvm_granule;
+}
+
 void pkvm_init_hyp_services(void)
 {
 	int i;
-- 
2.43.0