[RFC PATCH V2 02/18] x86/hyperv: Add sev-snp enlightened guest specific config

[Tianyu Lan <ltykernel@xxxxxxxxx>]

From: Tianyu Lan <tiala@xxxxxxxxxxxxx>

Introduce static key isolation_type_en_snp for enlightened
guest check and add some specific options in ms_hyperv_init_
platform().

Signed-off-by: Tianyu Lan <tiala@xxxxxxxxxxxxx>
---
 arch/x86/hyperv/ivm.c           | 12 +++++++++++-
 arch/x86/include/asm/mshyperv.h |  2 ++
 arch/x86/kernel/cpu/mshyperv.c  | 29 ++++++++++++++++++++++++-----
 drivers/hv/hv_common.c          |  7 +++++++
 4 files changed, 44 insertions(+), 6 deletions(-)

diff --git a/arch/x86/hyperv/ivm.c b/arch/x86/hyperv/ivm.c
index 1dbcbd9da74d..e9c30dad3419 100644
--- a/arch/x86/hyperv/ivm.c
+++ b/arch/x86/hyperv/ivm.c
@@ -259,10 +259,20 @@ bool hv_is_isolation_supported(void)
 }
 
 DEFINE_STATIC_KEY_FALSE(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);
+}
 
 /*
  * hv_isolation_type_snp - Check system runs in the AMD SEV-SNP based
- * isolation VM.
+ * isolation VM with vTOM support.
  */
 bool hv_isolation_type_snp(void)
 {
diff --git a/arch/x86/include/asm/mshyperv.h b/arch/x86/include/asm/mshyperv.h
index 61f0c206bff0..9b8c3f638845 100644
--- a/arch/x86/include/asm/mshyperv.h
+++ b/arch/x86/include/asm/mshyperv.h
@@ -14,6 +14,7 @@
 union hv_ghcb;
 
 DECLARE_STATIC_KEY_FALSE(isolation_type_snp);
+DECLARE_STATIC_KEY_FALSE(isolation_type_en_snp);
 
 typedef int (*hyperv_fill_flush_list_func)(
 		struct hv_guest_mapping_flush_list *flush,
@@ -32,6 +33,7 @@ extern u64 hv_current_partition_id;
 
 extern union hv_ghcb * __percpu *hv_ghcb_pg;
 
+extern bool hv_isolation_type_en_snp(void);
 int hv_call_deposit_pages(int node, u64 partition_id, u32 num_pages);
 int hv_call_add_logical_proc(int node, u32 lp_index, u32 acpi_id);
 int hv_call_create_vp(int node, u64 partition_id, u32 vp_index, u32 flags);
diff --git a/arch/x86/kernel/cpu/mshyperv.c b/arch/x86/kernel/cpu/mshyperv.c
index 831613959a92..2ea4f21c6172 100644
--- a/arch/x86/kernel/cpu/mshyperv.c
+++ b/arch/x86/kernel/cpu/mshyperv.c
@@ -273,6 +273,21 @@ static void __init ms_hyperv_init_platform(void)
 	ms_hyperv.misc_features = cpuid_edx(HYPERV_CPUID_FEATURES);
 	ms_hyperv.hints    = cpuid_eax(HYPERV_CPUID_ENLIGHTMENT_INFO);
 
+	/*
+	 * Add custom configuration for SEV-SNP Enlightened guest
+	 */
+	if (cc_platform_has(CC_ATTR_GUEST_SEV_SNP)) {
+		ms_hyperv.features |= HV_ACCESS_FREQUENCY_MSRS;
+		ms_hyperv.misc_features |= HV_FEATURE_FREQUENCY_MSRS_AVAILABLE;
+		ms_hyperv.misc_features &= ~HV_FEATURE_GUEST_CRASH_MSR_AVAILABLE;
+		ms_hyperv.hints |= HV_DEPRECATING_AEOI_RECOMMENDED;
+		ms_hyperv.hints |= HV_X64_APIC_ACCESS_RECOMMENDED;
+		ms_hyperv.hints |= HV_X64_CLUSTER_IPI_RECOMMENDED;
+	}
+
+	pr_info("Hyper-V: enlightment features 0x%x, hints 0x%x, misc 0x%x\n",
+		ms_hyperv.features, ms_hyperv.hints, ms_hyperv.misc_features);
+
 	hv_max_functions_eax = cpuid_eax(HYPERV_CPUID_VENDOR_AND_MAX_FUNCTIONS);
 
 	pr_info("Hyper-V: privilege flags low 0x%x, high 0x%x, hints 0x%x, misc 0x%x\n",
@@ -328,18 +343,22 @@ static void __init ms_hyperv_init_platform(void)
 		ms_hyperv.shared_gpa_boundary =
 			BIT_ULL(ms_hyperv.shared_gpa_boundary_bits);
 
-		pr_info("Hyper-V: Isolation Config: Group A 0x%x, Group B 0x%x\n",
-			ms_hyperv.isolation_config_a, ms_hyperv.isolation_config_b);
-
-		if (hv_get_isolation_type() == HV_ISOLATION_TYPE_SNP) {
+		if (cc_platform_has(CC_ATTR_GUEST_SEV_SNP)) {
+			static_branch_enable(&isolation_type_en_snp);
+		} else if (hv_get_isolation_type() == HV_ISOLATION_TYPE_SNP) {
 			static_branch_enable(&isolation_type_snp);
 #ifdef CONFIG_SWIOTLB
 			swiotlb_unencrypted_base = ms_hyperv.shared_gpa_boundary;
 #endif
 		}
+
+		pr_info("Hyper-V: Isolation Config: Group A 0x%x, Group B 0x%x\n",
+			ms_hyperv.isolation_config_a, ms_hyperv.isolation_config_b);
+
 		/* Isolation VMs are unenlightened SEV-based VMs, thus this check: */
 		if (IS_ENABLED(CONFIG_AMD_MEM_ENCRYPT)) {
-			if (hv_get_isolation_type() != HV_ISOLATION_TYPE_NONE)
+			if (hv_get_isolation_type() != HV_ISOLATION_TYPE_NONE
+			    && !cc_platform_has(CC_ATTR_GUEST_SEV_SNP))
 				cc_set_vendor(CC_VENDOR_HYPERV);
 		}
 	}
diff --git a/drivers/hv/hv_common.c b/drivers/hv/hv_common.c
index ae68298c0dca..2c6602571c47 100644
--- a/drivers/hv/hv_common.c
+++ b/drivers/hv/hv_common.c
@@ -268,6 +268,13 @@ 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);
+
+
 void __weak hv_setup_vmbus_handler(void (*handler)(void))
 {
 }
-- 
2.25.1