x86/hyperv: Remove hv_isolation_type_en_snp

In ms_hyperv_init_platform(), do not distinguish between a SNP VM with
the paravisor and a SNP VM without the paravisor.

Replace hv_isolation_type_en_snp() with
!ms_hyperv.paravisor_present && hv_isolation_type_snp().

The hv_isolation_type_en_snp() in drivers/hv/hv.c and
drivers/hv/hv_common.c can be changed to hv_isolation_type_snp() since
we know !ms_hyperv.paravisor_present is true there.
Signed-off-by: Dexuan Cui <decui@microsoft.com>
Reviewed-by: Michael Kelley <mikelley@microsoft.com>
Reviewed-by: Tianyu Lan <tiala@microsoft.com>
Signed-off-by: Wei Liu <wei.liu@kernel.org>
Link: https://lore.kernel.org/r/20230824080712.30327-10-decui@microsoft.com

arch/x86/hyperv/hv_init.c

@@ -52,7 +52,7 @@ static int hyperv_init_ghcb(void)
 	void *ghcb_va;
 	void **ghcb_base;
 
-	if (!hv_isolation_type_snp())
+	if (!ms_hyperv.paravisor_present || !hv_isolation_type_snp())
 		return 0;
 
 	if (!hv_ghcb_pg)
@@ -117,7 +117,7 @@ static int hv_cpu_init(unsigned int cpu)
 			 * is blocked to run in Confidential VM. So only decrypt assist
 			 * page in non-root partition here.
 			 */
-			if (*hvp && hv_isolation_type_en_snp()) {
+			if (*hvp && !ms_hyperv.paravisor_present && hv_isolation_type_snp()) {
 				WARN_ON_ONCE(set_memory_decrypted((unsigned long)(*hvp), 1));
 				memset(*hvp, 0, PAGE_SIZE);
 			}
@@ -460,7 +460,7 @@ void __init hyperv_init(void)
 			goto common_free;
 	}
 
-	if (hv_isolation_type_snp()) {
+	if (ms_hyperv.paravisor_present && hv_isolation_type_snp()) {
 		/* Negotiate GHCB Version. */
 		if (!hv_ghcb_negotiate_protocol())
 			hv_ghcb_terminate(SEV_TERM_SET_GEN,
@@ -583,7 +583,7 @@ void __init hyperv_init(void)
 	hv_query_ext_cap(0);
 
 	/* Find the VTL */
-	if (hv_isolation_type_en_snp())
+	if (!ms_hyperv.paravisor_present && hv_isolation_type_snp())
 		ms_hyperv.vtl = get_vtl();
 
 	return;

arch/x86/hyperv/ivm.c

@@ -637,7 +637,7 @@ bool hv_is_isolation_supported(void)
 DEFINE_STATIC_KEY_FALSE(isolation_type_snp);
 
 /*
- * hv_isolation_type_snp - Check system runs in the AMD SEV-SNP based
+ * hv_isolation_type_snp - Check if the system runs in an AMD SEV-SNP based
  * isolation VM.
  */
 bool hv_isolation_type_snp(void)
@@ -645,16 +645,6 @@ bool hv_isolation_type_snp(void)
 	return static_branch_unlikely(&isolation_type_snp);
 }
 
-DEFINE_STATIC_KEY_FALSE(isolation_type_en_snp);
-/*
- * hv_isolation_type_en_snp - Check system runs in the AMD SEV-SNP based
- * isolation enlightened VM.
- */
-bool hv_isolation_type_en_snp(void)
-{
-	return static_branch_unlikely(&isolation_type_en_snp);
-}
-
 DEFINE_STATIC_KEY_FALSE(isolation_type_tdx);
 /*
  * hv_isolation_type_tdx - Check if the system runs in an Intel TDX based

arch/x86/include/asm/mshyperv.h

@@ -26,7 +26,6 @@
 union hv_ghcb;
 
 DECLARE_STATIC_KEY_FALSE(isolation_type_snp);
-DECLARE_STATIC_KEY_FALSE(isolation_type_en_snp);
 DECLARE_STATIC_KEY_FALSE(isolation_type_tdx);
 
 typedef int (*hyperv_fill_flush_list_func)(
@@ -50,7 +49,7 @@ extern u64 hv_current_partition_id;
 
 extern union hv_ghcb * __percpu *hv_ghcb_pg;
 
-extern bool hv_isolation_type_en_snp(void);
+bool hv_isolation_type_snp(void);
 bool hv_isolation_type_tdx(void);
 u64 hv_tdx_hypercall(u64 control, u64 param1, u64 param2);
 
@@ -79,7 +78,7 @@ static inline u64 hv_do_hypercall(u64 control, void *input, void *output)
 	if (hv_isolation_type_tdx() && !hyperv_paravisor_present)
 		return hv_tdx_hypercall(control, input_address, output_address);
 
-	if (hv_isolation_type_en_snp()) {
+	if (hv_isolation_type_snp() && !hyperv_paravisor_present) {
 		__asm__ __volatile__("mov %4, %%r8\n"
 				     "vmmcall"
 				     : "=a" (hv_status), ASM_CALL_CONSTRAINT,
@@ -135,7 +134,7 @@ static inline u64 _hv_do_fast_hypercall8(u64 control, u64 input1)
 	if (hv_isolation_type_tdx() && !hyperv_paravisor_present)
 		return hv_tdx_hypercall(control, input1, 0);
 
-	if (hv_isolation_type_en_snp()) {
+	if (hv_isolation_type_snp() && !hyperv_paravisor_present) {
 		__asm__ __volatile__(
 				"vmmcall"
 				: "=a" (hv_status), ASM_CALL_CONSTRAINT,
@@ -189,7 +188,7 @@ static inline u64 _hv_do_fast_hypercall16(u64 control, u64 input1, u64 input2)
 	if (hv_isolation_type_tdx() && !hyperv_paravisor_present)
 		return hv_tdx_hypercall(control, input1, input2);
 
-	if (hv_isolation_type_en_snp()) {
+	if (hv_isolation_type_snp() && !hyperv_paravisor_present) {
 		__asm__ __volatile__("mov %4, %%r8\n"
 				     "vmmcall"
 				     : "=a" (hv_status), ASM_CALL_CONSTRAINT,
@@ -284,8 +283,6 @@ static inline void hv_ghcb_terminate(unsigned int set, unsigned int reason) {}
 static inline int hv_snp_boot_ap(int cpu, unsigned long start_ip) { return 0; }
 #endif
 
-extern bool hv_isolation_type_snp(void);
-
 #if defined(CONFIG_AMD_MEM_ENCRYPT) || defined(CONFIG_INTEL_TDX_GUEST)
 void hv_vtom_init(void);
 void hv_ivm_msr_write(u64 msr, u64 value);

arch/x86/kernel/cpu/mshyperv.c

@@ -304,7 +304,7 @@ static void __init hv_smp_prepare_cpus(unsigned int max_cpus)
 	 *  Override wakeup_secondary_cpu_64 callback for SEV-SNP
 	 *  enlightened guest.
 	 */
-	if (hv_isolation_type_en_snp()) {
+	if (!ms_hyperv.paravisor_present && hv_isolation_type_snp()) {
 		apic->wakeup_secondary_cpu_64 = hv_snp_boot_ap;
 		return;
 	}
@@ -440,10 +440,7 @@ static void __init ms_hyperv_init_platform(void)
 
 
 		if (hv_get_isolation_type() == HV_ISOLATION_TYPE_SNP) {
-			if (ms_hyperv.paravisor_present)
-				static_branch_enable(&isolation_type_snp);
-			else
-				static_branch_enable(&isolation_type_en_snp);
+			static_branch_enable(&isolation_type_snp);
 		} else if (hv_get_isolation_type() == HV_ISOLATION_TYPE_TDX) {
 			static_branch_enable(&isolation_type_tdx);
 
@@ -556,7 +553,8 @@ static void __init ms_hyperv_init_platform(void)
 
 # ifdef CONFIG_SMP
 	smp_ops.smp_prepare_boot_cpu = hv_smp_prepare_boot_cpu;
-	if (hv_root_partition || hv_isolation_type_en_snp())
+	if (hv_root_partition ||
+	    (!ms_hyperv.paravisor_present && hv_isolation_type_snp()))
 		smp_ops.smp_prepare_cpus = hv_smp_prepare_cpus;
 # endif
 

drivers/hv/hv.c

@@ -164,7 +164,7 @@ int hv_synic_alloc(void)
 		}
 
 		if (!ms_hyperv.paravisor_present &&
-		    (hv_isolation_type_en_snp() || hv_isolation_type_tdx())) {
+		    (hv_isolation_type_snp() || hv_isolation_type_tdx())) {
 			ret = set_memory_decrypted((unsigned long)
 				hv_cpu->synic_message_page, 1);
 			if (ret) {
@@ -225,7 +225,7 @@ void hv_synic_free(void)
 		}
 
 		if (!ms_hyperv.paravisor_present &&
-		    (hv_isolation_type_en_snp() || hv_isolation_type_tdx())) {
+		    (hv_isolation_type_snp() || hv_isolation_type_tdx())) {
 			if (hv_cpu->synic_message_page) {
 				ret = set_memory_encrypted((unsigned long)
 					hv_cpu->synic_message_page, 1);

drivers/hv/hv_common.c

@@ -383,7 +383,7 @@ int hv_common_cpu_init(unsigned int cpu)
 		}
 
 		if (!ms_hyperv.paravisor_present &&
-		    (hv_isolation_type_en_snp() || hv_isolation_type_tdx())) {
+		    (hv_isolation_type_snp() || hv_isolation_type_tdx())) {
 			ret = set_memory_decrypted((unsigned long)mem, pgcount);
 			if (ret) {
 				/* It may be unsafe to free 'mem' */
@@ -532,12 +532,6 @@ bool __weak hv_isolation_type_snp(void)
 }
 EXPORT_SYMBOL_GPL(hv_isolation_type_snp);
 
-bool __weak hv_isolation_type_en_snp(void)
-{
-	return false;
-}
-EXPORT_SYMBOL_GPL(hv_isolation_type_en_snp);
-
 bool __weak hv_isolation_type_tdx(void)
 {
 	return false;

include/asm-generic/mshyperv.h

@@ -64,8 +64,7 @@ extern void * __percpu *hyperv_pcpu_output_arg;
 
 extern u64 hv_do_hypercall(u64 control, void *inputaddr, void *outputaddr);
 extern u64 hv_do_fast_hypercall8(u16 control, u64 input8);
-extern bool hv_isolation_type_snp(void);
-extern bool hv_isolation_type_en_snp(void);
+bool hv_isolation_type_snp(void);
 bool hv_isolation_type_tdx(void);
 
 /* Helper functions that provide a consistent pattern for checking Hyper-V hypercall status. */