[PATCH V5 2/5] x86/hyper-v: Add hyperv Isolation VM check in the cc_platform_has()

[Tianyu Lan <ltykernel@xxxxxxxxx>]

From: Tianyu Lan <Tianyu.Lan@xxxxxxxxxxxxx>

Hyper-V provides Isolation VM which has memory encrypt support. Add
hyperv_cc_platform_has() and return true for check of GUEST_MEM_ENCRYPT
attribute.

Signed-off-by: Tianyu Lan <Tianyu.Lan@xxxxxxxxxxxxx>
---
Change since v3:
	* Change code style of checking GUEST_MEM attribute in the
	  hyperv_cc_platform_has().
---
 arch/x86/kernel/cc_platform.c | 12 ++++++++++++
 1 file changed, 12 insertions(+)

diff --git a/arch/x86/kernel/cc_platform.c b/arch/x86/kernel/cc_platform.c
index 03bb2f343ddb..7b66793c0f25 100644
--- a/arch/x86/kernel/cc_platform.c
+++ b/arch/x86/kernel/cc_platform.c
@@ -11,6 +11,7 @@
 #include <linux/cc_platform.h>
 #include <linux/mem_encrypt.h>
 
+#include <asm/mshyperv.h>
 #include <asm/processor.h>
 
 static bool __maybe_unused intel_cc_platform_has(enum cc_attr attr)
@@ -58,9 +59,20 @@ static bool amd_cc_platform_has(enum cc_attr attr)
 #endif
 }
 
+static bool hyperv_cc_platform_has(enum cc_attr attr)
+{
+#if IS_ENABLED(CONFIG_HYPERV)
+	return attr == CC_ATTR_GUEST_MEM_ENCRYPT;
+#else
+	return false;
+#endif
+}
 
 bool cc_platform_has(enum cc_attr attr)
 {
+	if (hv_is_isolation_supported())
+		return hyperv_cc_platform_has(attr);
+
 	if (sme_me_mask)
 		return amd_cc_platform_has(attr);
 
-- 
2.25.1