[PATCH v3 09/10] x86/hyperv: Remove hv_isolation_type_en_snp

Dexuan Cui
2023-08-24T08:11:34Z

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>
---

Changes in v2:
Rebased to Tianyu's v7 SNP patchset: the changes are small.
In hyperv_init_ghcb() and hyperv_init(), added the test of
hyperv_paravisor_present, which was missed in v1.
Updated the test before the call of get_vtl().
Updated the test in hv_do_hypercall() and friends.
Updated the test for hv_smp_prepare_cpus().

Changes in v3:
hyperv_paravisor_present -> ms_hyperv.paravisor_present

arch/x86/hyperv/hv_init.c | 8 ++++----
arch/x86/hyperv/ivm.c | 12 +-----------
arch/x86/include/asm/mshyperv.h | 11 ++++-------
arch/x86/kernel/cpu/mshyperv.c | 10 ++++------
drivers/hv/hv.c | 4 ++--
drivers/hv/hv_common.c | 8 +-------
include/asm-generic/mshyperv.h | 3 +--
7 files changed, 17 insertions(+), 39 deletions(-)

diff --git a/arch/x86/hyperv/hv_init.c b/arch/x86/hyperv/hv_init.c
index c4cffa3b1c3c..2b0124394e24 100644
--- a/arch/x86/hyperv/hv_init.c
+++ b/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;
diff --git a/arch/x86/hyperv/ivm.c b/arch/x86/hyperv/ivm.c
index fbc07493fcb4..3d48f823582c 100644
--- a/arch/x86/hyperv/ivm.c
+++ b/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
diff --git a/arch/x86/include/asm/mshyperv.h b/arch/x86/include/asm/mshyperv.h
index 101f71b85cfd..66ca641a164a 100644
--- a/arch/x86/include/asm/mshyperv.h
+++ b/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);
diff --git a/arch/x86/kernel/cpu/mshyperv.c b/arch/x86/kernel/cpu/mshyperv.c
index 4f51dac9eeb2..b63590ffc777 100644
--- a/arch/x86/kernel/cpu/mshyperv.c
+++ b/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

diff --git a/drivers/hv/hv.c b/drivers/hv/hv.c
index 523c5d99f375..51e5018ac9b2 100644
--- a/drivers/hv/hv.c
+++ b/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);
diff --git a/drivers/hv/hv_common.c b/drivers/hv/hv_common.c
index e62d64753902..81aa8be3e0df 100644
--- a/drivers/hv/hv_common.c
+++ b/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;
diff --git a/include/asm-generic/mshyperv.h b/include/asm-generic/mshyperv.h
index f577eff58ea0..e7ecf03f675e 100644
--- a/include/asm-generic/mshyperv.h
+++ b/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. */
--
2.25.1