[PATCH V1 1/2] Drivers: hv: Add new function hv_isolation_type_hw()

[Mukesh R <mrathor@linux.microsoft.com>]

Add a new function hv_isolation_type_hw() for convenient check of
whether a VM is running in HW confidential mode, ie, TDX or SNP on x86
or RME on ARM.

Signed-off-by: Mukesh R <mrathor@linux.microsoft.com>
---
 arch/x86/hyperv/ivm.c          | 5 +++++
 drivers/hv/hv_common.c         | 9 +++++++--
 include/asm-generic/mshyperv.h | 7 +++++++
 3 files changed, 19 insertions(+), 2 deletions(-)

diff --git a/arch/x86/hyperv/ivm.c b/arch/x86/hyperv/ivm.c
index 2ce4dfe53472..26e570cf77be 100644
--- a/arch/x86/hyperv/ivm.c
+++ b/arch/x86/hyperv/ivm.c
@@ -944,3 +944,8 @@ bool hv_isolation_type_tdx(void)
 {
 	return static_branch_unlikely(&isolation_type_tdx);
 }
+
+bool hv_isolation_type_hw(void)
+{
+	return hv_isolation_type_snp() || hv_isolation_type_tdx();
+}
diff --git a/drivers/hv/hv_common.c b/drivers/hv/hv_common.c
index 27b9b79d4f4c..b537cafdc2a2 100644
--- a/drivers/hv/hv_common.c
+++ b/drivers/hv/hv_common.c
@@ -528,8 +528,7 @@ int hv_common_cpu_init(unsigned int cpu)
 			*outputarg = (char *)mem + HV_HYP_PAGE_SIZE;
 		}
 
-		if (!ms_hyperv.paravisor_present &&
-		    (hv_isolation_type_snp() || hv_isolation_type_tdx())) {
+		if (!ms_hyperv.paravisor_present && hv_isolation_type_hw()) {
 			ret = set_memory_decrypted((unsigned long)mem, pgcount);
 			if (ret) {
 				/* It may be unsafe to free 'mem' */
@@ -696,6 +695,12 @@ bool __weak hv_isolation_type_tdx(void)
 }
 EXPORT_SYMBOL_GPL(hv_isolation_type_tdx);
 
+bool __weak hv_isolation_type_hw(void)
+{
+	return false;
+}
+EXPORT_SYMBOL_GPL(hv_isolation_type_hw);
+
 void __weak hv_setup_vmbus_handler(void (*handler)(void))
 {
 }
diff --git a/include/asm-generic/mshyperv.h b/include/asm-generic/mshyperv.h
index 4c9f3353074a..396bcb3db0bc 100644
--- a/include/asm-generic/mshyperv.h
+++ b/include/asm-generic/mshyperv.h
@@ -84,6 +84,13 @@ u64 hv_do_fast_hypercall16(u16 control, u64 input1, u64 input2);
 bool hv_isolation_type_snp(void);
 bool hv_isolation_type_tdx(void);
 
+/* This needs to be before hv_do_rep_hypercall() below */
+#if IS_ENABLED(CONFIG_HYPERV)
+bool hv_isolation_type_hw(void);
+#else
+static inline bool hv_isolation_type_hw(void) { return false; }
+#endif
+
 /*
  * On architectures where Hyper-V doesn't support AEOI (e.g., ARM64),
  * it doesn't provide a recommendation flag and AEOI must be disabled.
-- 
2.51.2.vfs.0.1