[PATCH v2 9/9] x86/hyperv: Remove hv_isolation_type_en_snp

Dexuan Cui
2023-08-20T20:33:27Z

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
!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 !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().

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 | 9 ++++-----
drivers/hv/hv.c | 4 ++--
drivers/hv/hv_common.c | 8 +-------
include/asm-generic/mshyperv.h | 3 +--
7 files changed, 17 insertions(+), 38 deletions(-)

diff --git a/arch/x86/hyperv/hv_init.c b/arch/x86/hyperv/hv_init.c
index 18afbb10edc64..fd79e632023e2 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 (!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 && !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 (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 (!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 93d54d8ef12e1..7d1f553ec0017 100644
--- a/arch/x86/hyperv/ivm.c
+++ b/arch/x86/hyperv/ivm.c
@@ -624,7 +624,7 @@ 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)
@@ -632,16 +632,6 @@ 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 18f569c44c39d..f0b3782884d22 100644
--- a/arch/x86/include/asm/mshyperv.h
+++ b/arch/x86/include/asm/mshyperv.h
@@ -27,7 +27,6 @@
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)(
@@ -51,7 +50,7 @@ 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);

@@ -82,7 +81,7 @@ static inline u64 hv_do_hypercall(u64 control, void *input, void *output)
cc_mkdec(input_address),
cc_mkdec(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,
@@ -140,7 +139,7 @@ static inline u64 _hv_do_fast_hypercall8(u64 control, u64 input1)
control == (HVCALL_SIGNAL_EVENT | HV_HYPERCALL_FAST_BIT)))
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,
@@ -194,7 +193,7 @@ 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,
@@ -295,8 +294,6 @@ static inline void hv_vtom_init(void) {}
static int hv_snp_boot_ap(int cpu, unsigned long start_ip) { return 0; }
#endif

-extern bool hv_isolation_type_snp(void);
-
static inline bool hv_is_synic_reg(unsigned int reg)
{
return (reg >= HV_REGISTER_SCONTROL) &&
diff --git a/arch/x86/kernel/cpu/mshyperv.c b/arch/x86/kernel/cpu/mshyperv.c
index a196760afa7a1..c98a75ae948e4 100644
--- a/arch/x86/kernel/cpu/mshyperv.c
+++ b/arch/x86/kernel/cpu/mshyperv.c
@@ -306,7 +306,7 @@ 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 (!hyperv_paravisor_present && hv_isolation_type_snp()) {
apic->wakeup_secondary_cpu_64 = hv_snp_boot_ap;
return;
}
@@ -441,9 +441,7 @@ static void __init ms_hyperv_init_platform(void)
ms_hyperv.isolation_config_a, ms_hyperv.isolation_config_b);

- 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) {
+ 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);
@@ -566,7 +564,8 @@ 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 ||
+ (!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 6b5f1805d4749..932b8bc239acb 100644
--- a/drivers/hv/hv.c
+++ b/drivers/hv/hv.c
@@ -166,7 +166,7 @@ int hv_synic_alloc(void)
}

if (!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) {
@@ -227,7 +227,7 @@ void hv_synic_free(void)
}

if (!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 c0b0ac44ffa3c..d3f95a1be1e99 100644
--- a/drivers/hv/hv_common.c
+++ b/drivers/hv/hv_common.c
@@ -386,7 +386,7 @@ int hv_common_cpu_init(unsigned int cpu)
}

if (!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' */
@@ -535,12 +535,6 @@ 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 94f87a0344590..ac271f3b4091c 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