[PATCH v6 1/8] x86/hyperv: Add sev-snp enlightened guest static key

Tianyu Lan
2023-08-16T16:00:11Z

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

Reviewed-by: Michael Kelley <mikelley@microsoft.com>
Signed-off-by: Tianyu Lan <tiala@microsoft.com>
---
arch/x86/hyperv/ivm.c | 11 +++++++++++
arch/x86/include/asm/mshyperv.h | 2 ++
arch/x86/kernel/cpu/mshyperv.c | 9 +++++++--
drivers/hv/hv_common.c | 6 ++++++
include/asm-generic/mshyperv.h | 13 ++++++++++---
5 files changed, 36 insertions(+), 5 deletions(-)

diff --git a/arch/x86/hyperv/ivm.c b/arch/x86/hyperv/ivm.c
index 14f46ad2ca64..b2b5cb19fac9 100644
--- a/arch/x86/hyperv/ivm.c
+++ b/arch/x86/hyperv/ivm.c
@@ -413,3 +413,14 @@ 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 88d9ef98e087..9f11f0495950 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,
@@ -239,6 +240,7 @@ static inline void hv_vtom_init(void) {}
#endif

extern bool hv_isolation_type_snp(void);
+extern bool hv_isolation_type_en_snp(void);

static inline bool hv_is_synic_reg(unsigned int reg)
{
diff --git a/arch/x86/kernel/cpu/mshyperv.c b/arch/x86/kernel/cpu/mshyperv.c
index c7969e806c64..5398fb2f4d39 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) &&
+ ms_hyperv.paravisor_present))
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 542a1d53b303..4b4aa53c34c2 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))
{
}
diff --git a/include/asm-generic/mshyperv.h b/include/asm-generic/mshyperv.h
index 402a8c1c202d..580c766958de 100644
--- a/include/asm-generic/mshyperv.h
+++ b/include/asm-generic/mshyperv.h
@@ -36,15 +36,21 @@ struct ms_hyperv_info {
u32 nested_features;
u32 max_vp_index;
u32 max_lp_index;
- u32 isolation_config_a;
+ union {
+ u32 isolation_config_a;
+ struct {
+ u32 paravisor_present : 1;
+ u32 reserved_a1 : 31;
+ };
+ };
union {
u32 isolation_config_b;
struct {
u32 cvm_type : 4;
- u32 reserved1 : 1;
+ u32 reserved_b1 : 1;
u32 shared_gpa_boundary_active : 1;
u32 shared_gpa_boundary_bits : 6;
- u32 reserved2 : 20;
+ u32 reserved_b2 : 20;
};
};
u64 shared_gpa_boundary;
@@ -58,6 +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);

/* Helper functions that provide a consistent pattern for checking Hyper-V hypercall status. */
static inline int hv_result(u64 status)
--
2.25.1