[PATCH v6 3/6] x86/hyperv: Add hv_isolation_type_tdx() to detect TDX guests

Dexuan Cui
2023-05-04T22:55:08Z

No logic change to SNP/VBS guests.

hv_isolation_type_tdx() wil be used to instruct a TDX guest on Hyper-V to
do some TDX-specific operations, e.g. hv_do_hypercall() should use
__tdx_hypercall(), and a TDX guest on Hyper-V should handle the Hyper-V
Event/Message/Monitor pages specially.

Reviewed-by: Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@linux.intel.com>
Reviewed-by: Michael Kelley <mikelley@microsoft.com>
Signed-off-by: Dexuan Cui <decui@microsoft.com>
---

Changes in v2:
Added "#ifdef CONFIG_INTEL_TDX_GUEST and #endif" for
hv_isolation_type_tdx() in arch/x86/hyperv/ivm.c.

Simplified the changes in ms_hyperv_init_platform().

Changes in v3:
Added Kuppuswamy's Reviewed-by.

Changes in v4:
A minor rebase to Michael's v7 DDA patchset.

Changes in v5:
Added Michael's Reviewed-by.

Changes in v6: None.

arch/x86/hyperv/ivm.c | 6 ++++++
arch/x86/include/asm/hyperv-tlfs.h | 3 ++-
arch/x86/include/asm/mshyperv.h | 3 +++
arch/x86/kernel/cpu/mshyperv.c | 2 ++
drivers/hv/hv_common.c | 6 ++++++
include/asm-generic/mshyperv.h | 1 +
6 files changed, 20 insertions(+), 1 deletion(-)

diff --git a/arch/x86/hyperv/ivm.c b/arch/x86/hyperv/ivm.c
index cc92388b7a99..952117ce2d80 100644
--- a/arch/x86/hyperv/ivm.c
+++ b/arch/x86/hyperv/ivm.c
@@ -400,6 +400,7 @@ bool hv_is_isolation_supported(void)
}

DEFINE_STATIC_KEY_FALSE(isolation_type_snp);
+DEFINE_STATIC_KEY_FALSE(isolation_type_tdx);

/*
* hv_isolation_type_snp - Check system runs in the AMD SEV-SNP based
@@ -409,3 +410,8 @@ bool hv_isolation_type_snp(void)
{
return static_branch_unlikely(&isolation_type_snp);
}
+
+bool hv_isolation_type_tdx(void)
+{
+ return static_branch_unlikely(&isolation_type_tdx);
+}
diff --git a/arch/x86/include/asm/hyperv-tlfs.h b/arch/x86/include/asm/hyperv-tlfs.h
index cea95dcd27c2..ebb6d24fe352 100644
--- a/arch/x86/include/asm/hyperv-tlfs.h
+++ b/arch/x86/include/asm/hyperv-tlfs.h
@@ -169,7 +169,8 @@
enum hv_isolation_type {
HV_ISOLATION_TYPE_NONE = 0,
HV_ISOLATION_TYPE_VBS = 1,
- HV_ISOLATION_TYPE_SNP = 2
+ HV_ISOLATION_TYPE_SNP = 2,
+ HV_ISOLATION_TYPE_TDX = 3
};

/* Hyper-V specific model specific registers (MSRs) */
diff --git a/arch/x86/include/asm/mshyperv.h b/arch/x86/include/asm/mshyperv.h
index 49bb4f2bd300..231e56631295 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_tdx);

typedef int (*hyperv_fill_flush_list_func)(
struct hv_guest_mapping_flush_list *flush,
@@ -47,6 +48,8 @@ extern u64 hv_current_partition_id;

extern union hv_ghcb * __percpu *hv_ghcb_pg;

+extern bool hv_isolation_type_tdx(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 c7969e806c64..2fd687a80033 100644
--- a/arch/x86/kernel/cpu/mshyperv.c
+++ b/arch/x86/kernel/cpu/mshyperv.c
@@ -404,6 +404,8 @@ static void __init ms_hyperv_init_platform(void)

if (hv_get_isolation_type() == HV_ISOLATION_TYPE_SNP)
static_branch_enable(&isolation_type_snp);
+ else if (hv_get_isolation_type() == HV_ISOLATION_TYPE_TDX)
+ static_branch_enable(&isolation_type_tdx);
}

if (hv_max_functions_eax >= HYPERV_CPUID_NESTED_FEATURES) {
diff --git a/drivers/hv/hv_common.c b/drivers/hv/hv_common.c
index 64f9ceca887b..6156114cd9c5 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_tdx(void)
+{
+ return false;
+}
+EXPORT_SYMBOL_GPL(hv_isolation_type_tdx);
+
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..3449a8a27c03 100644
--- a/include/asm-generic/mshyperv.h
+++ b/include/asm-generic/mshyperv.h
@@ -58,6 +58,7 @@ 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_tdx(void);

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