[RFC PATCH V5 01/15] x86/hyperv: Add sev-snp enlightened guest static key

Tianyu Lan
2023-05-01T08:57:43Z

From: Tianyu Lan <tiala@microsoft.com>

Introduce static key isolation_type_en_snp for enlightened
sev-snp guest check.

Signed-off-by: Tianyu Lan <tiala@microsoft.com>
---
Change since RFC-v3:
* Remove some Hyper-V specific config setting
---
arch/x86/hyperv/ivm.c | 11 +++++++++++
arch/x86/include/asm/mshyperv.h | 3 +++
arch/x86/kernel/cpu/mshyperv.c | 9 +++++++--
drivers/hv/hv_common.c | 6 ++++++
4 files changed, 27 insertions(+), 2 deletions(-)

diff --git a/arch/x86/hyperv/ivm.c b/arch/x86/hyperv/ivm.c
index 127d5b7b63de..368b2731950e 100644
--- a/arch/x86/hyperv/ivm.c
+++ b/arch/x86/hyperv/ivm.c
@@ -409,3 +409,14 @@ 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);
+}
+
diff --git a/arch/x86/include/asm/mshyperv.h b/arch/x86/include/asm/mshyperv.h
index b445e252aa83..97d117ec95c4 100644
--- a/arch/x86/include/asm/mshyperv.h
+++ b/arch/x86/include/asm/mshyperv.h
@@ -26,6 +26,7 @@
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,
@@ -45,6 +46,8 @@ extern void *hv_hypercall_pg;

extern u64 hv_current_partition_id;

+extern bool hv_isolation_type_en_snp(void);
+
extern union hv_ghcb * __percpu *hv_ghcb_pg;

int hv_call_deposit_pages(int node, u64 partition_id, u32 num_pages);
diff --git a/arch/x86/kernel/cpu/mshyperv.c b/arch/x86/kernel/cpu/mshyperv.c
index c7969e806c64..63a2bfbfe701 100644
--- a/arch/x86/kernel/cpu/mshyperv.c
+++ b/arch/x86/kernel/cpu/mshyperv.c
@@ -402,8 +402,12 @@ static void __init ms_hyperv_init_platform(void)
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);
+ }
}

if (hv_max_functions_eax >= HYPERV_CPUID_NESTED_FEATURES) {
@@ -473,7 +477,8 @@ static void __init ms_hyperv_init_platform(void)

#if IS_ENABLED(CONFIG_HYPERV)
if ((hv_get_isolation_type() == HV_ISOLATION_TYPE_VBS) ||
- (hv_get_isolation_type() == HV_ISOLATION_TYPE_SNP))
+ (hv_get_isolation_type() == HV_ISOLATION_TYPE_SNP
+ && !cc_platform_has(CC_ATTR_GUEST_SEV_SNP)))
hv_vtom_init();
/*
* Setup the hook to get control post apic initialization.
diff --git a/drivers/hv/hv_common.c b/drivers/hv/hv_common.c
index 64f9ceca887b..179bc5f5bf52 100644
--- a/drivers/hv/hv_common.c
+++ b/drivers/hv/hv_common.c
@@ -502,6 +502,12 @@ 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