Re: [RFC PATCH 5/12] HV: Add ghcb hvcall support for SNP VM
On 3/4/2021 1:21 AM, Vitaly Kuznetsov wrote:
Tianyu Lan writes:
From: Tianyu Lan
Hyper-V provides ghcb hvcall to handle VMBus
HVCALL_SIGNAL_EVENT and HVCALL_POST_MESSAGE
msg in SNP Isolation VM. Add such support.
Signed-off-by: Tianyu Lan
---
arch/x86/hyperv/ivm.c | 69 +
arch/x86/include/asm/mshyperv.h | 1 +
drivers/hv/connection.c | 6 ++-
drivers/hv/hv.c | 8 +++-
4 files changed, 82 insertions(+), 2 deletions(-)
diff --git a/arch/x86/hyperv/ivm.c b/arch/x86/hyperv/ivm.c
index 4332bf7aaf9b..feaabcd151f5 100644
--- a/arch/x86/hyperv/ivm.c
+++ b/arch/x86/hyperv/ivm.c
@@ -14,8 +14,77 @@
union hv_ghcb {
struct ghcb ghcb;
+ struct {
+ u64 hypercalldata[509];
+ u64 outputgpa;
+ union {
+ union {
+ struct {
+ u32 callcode: 16;
+ u32 isfast : 1;
+ u32 reserved1 : 14;
+ u32 isnested: 1;
+ u32 countofelements : 12;
+ u32 reserved2 : 4;
+ u32 repstartindex : 12;
+ u32 reserved3 : 4;
+ };
+ u64 asuint64;
+ } hypercallinput;
+ union {
+ struct {
+ u16 callstatus;
+ u16 reserved1;
+ u32 elementsprocessed : 12;
+ u32 reserved2 : 20;
+ };
+ u64 asunit64;
+ } hypercalloutput;
+ };
+ u64 reserved2;
+ } hypercall;
} __packed __aligned(PAGE_SIZE);
+u64 hv_ghcb_hypercall(u64 control, void *input, void *output, u32 input_size)
+{
+ union hv_ghcb *hv_ghcb;
+ void **ghcb_base;
+ unsigned long flags;
+
+ if (!ms_hyperv.ghcb_base)
+ return -EFAULT;
+
+ local_irq_save(flags);
+ ghcb_base = (void **)this_cpu_ptr(ms_hyperv.ghcb_base);
+ hv_ghcb = (union hv_ghcb *)*ghcb_base;
+ if (!hv_ghcb) {
+ local_irq_restore(flags);
+ return -EFAULT;
+ }
+
+ memset(hv_ghcb, 0x00, HV_HYP_PAGE_SIZE);
+ hv_ghcb->ghcb.protocol_version = 1;
+ hv_ghcb->ghcb.ghcb_usage = 1;
+
+ hv_ghcb->hypercall.outputgpa = (u64)output;
+ hv_ghcb->hypercall.hypercallinput.asuint64 = 0;
+ hv_ghcb->hypercall.hypercallinput.callcode = control;
+
+ if (input_size)
+ memcpy(hv_ghcb->hypercall.hypercalldata, input, input_size);
+
+ VMGEXIT();
+
+ hv_ghcb->ghcb.ghcb_usage = 0x;
+ memset(hv_ghcb->ghcb.save.valid_bitmap, 0,
+ sizeof(hv_ghcb->ghcb.save.valid_bitmap));
+
+ local_irq_restore(flags);
+
+ return hv_ghcb->hypercall.hypercalloutput.callstatus;
+}
+EXPORT_SYMBOL_GPL(hv_ghcb_hypercall);
+
void hv_ghcb_msr_write(u64 msr, u64 value)
{
union hv_ghcb *hv_ghcb;
diff --git a/arch/x86/include/asm/mshyperv.h b/arch/x86/include/asm/mshyperv.h
index f624d72b99d3..c8f66d269e5b 100644
--- a/arch/x86/include/asm/mshyperv.h
+++ b/arch/x86/include/asm/mshyperv.h
@@ -274,6 +274,7 @@ void hv_sint_rdmsrl_ghcb(u64 msr, u64 *value);
void hv_signal_eom_ghcb(void);
void hv_ghcb_msr_write(u64 msr, u64 value);
void hv_ghcb_msr_read(u64 msr, u64 *value);
+u64 hv_ghcb_hypercall(u64 control, void *input, void *output, u32 input_size);
#define hv_get_synint_state_ghcb(int_num, val) \
hv_sint_rdmsrl_ghcb(HV_X64_MSR_SINT0 + int_num, val)
diff --git a/drivers/hv/connection.c b/drivers/hv/connection.c
index c83612cddb99..79bca653dce9 100644
--- a/drivers/hv/connection.c
+++ b/drivers/hv/connection.c
@@ -442,6 +442,10 @@ void vmbus_set_event(struct vmbus_channel *channel)
++channel->sig_events;
- hv_do_fast_hypercall8(HVCALL_SIGNAL_EVENT, channel->sig_event);
+ if (hv_isolation_type_snp())
+ hv_ghcb_hypercall(HVCALL_SIGNAL_EVENT, >sig_event,
+ NULL, sizeof(u64));
+ else
+ hv_do_fast_hypercall8(HVCALL_SIGNAL_EVENT, channel->sig_event);
vmbus_set_event() is a hotpath so I'd suggest we introduce a static
branch instead of checking hv_isolation_type_snp() every time.
Good suggestion. Will add it in the next version. Thanks.
Re: [RFC PATCH 5/12] HV: Add ghcb hvcall support for SNP VM
Tianyu Lan writes:
> From: Tianyu Lan
>
> Hyper-V provides ghcb hvcall to handle VMBus
> HVCALL_SIGNAL_EVENT and HVCALL_POST_MESSAGE
> msg in SNP Isolation VM. Add such support.
>
> Signed-off-by: Tianyu Lan
> ---
> arch/x86/hyperv/ivm.c | 69 +
> arch/x86/include/asm/mshyperv.h | 1 +
> drivers/hv/connection.c | 6 ++-
> drivers/hv/hv.c | 8 +++-
> 4 files changed, 82 insertions(+), 2 deletions(-)
>
> diff --git a/arch/x86/hyperv/ivm.c b/arch/x86/hyperv/ivm.c
> index 4332bf7aaf9b..feaabcd151f5 100644
> --- a/arch/x86/hyperv/ivm.c
> +++ b/arch/x86/hyperv/ivm.c
> @@ -14,8 +14,77 @@
>
> union hv_ghcb {
> struct ghcb ghcb;
> + struct {
> + u64 hypercalldata[509];
> + u64 outputgpa;
> + union {
> + union {
> + struct {
> + u32 callcode: 16;
> + u32 isfast : 1;
> + u32 reserved1 : 14;
> + u32 isnested: 1;
> + u32 countofelements : 12;
> + u32 reserved2 : 4;
> + u32 repstartindex : 12;
> + u32 reserved3 : 4;
> + };
> + u64 asuint64;
> + } hypercallinput;
> + union {
> + struct {
> + u16 callstatus;
> + u16 reserved1;
> + u32 elementsprocessed : 12;
> + u32 reserved2 : 20;
> + };
> + u64 asunit64;
> + } hypercalloutput;
> + };
> + u64 reserved2;
> + } hypercall;
> } __packed __aligned(PAGE_SIZE);
>
> +u64 hv_ghcb_hypercall(u64 control, void *input, void *output, u32 input_size)
> +{
> + union hv_ghcb *hv_ghcb;
> + void **ghcb_base;
> + unsigned long flags;
> +
> + if (!ms_hyperv.ghcb_base)
> + return -EFAULT;
> +
> + local_irq_save(flags);
> + ghcb_base = (void **)this_cpu_ptr(ms_hyperv.ghcb_base);
> + hv_ghcb = (union hv_ghcb *)*ghcb_base;
> + if (!hv_ghcb) {
> + local_irq_restore(flags);
> + return -EFAULT;
> + }
> +
> + memset(hv_ghcb, 0x00, HV_HYP_PAGE_SIZE);
> + hv_ghcb->ghcb.protocol_version = 1;
> + hv_ghcb->ghcb.ghcb_usage = 1;
> +
> + hv_ghcb->hypercall.outputgpa = (u64)output;
> + hv_ghcb->hypercall.hypercallinput.asuint64 = 0;
> + hv_ghcb->hypercall.hypercallinput.callcode = control;
> +
> + if (input_size)
> + memcpy(hv_ghcb->hypercall.hypercalldata, input, input_size);
> +
> + VMGEXIT();
> +
> + hv_ghcb->ghcb.ghcb_usage = 0x;
> + memset(hv_ghcb->ghcb.save.valid_bitmap, 0,
> +sizeof(hv_ghcb->ghcb.save.valid_bitmap));
> +
> + local_irq_restore(flags);
> +
> + return hv_ghcb->hypercall.hypercalloutput.callstatus;
> +}
> +EXPORT_SYMBOL_GPL(hv_ghcb_hypercall);
> +
> void hv_ghcb_msr_write(u64 msr, u64 value)
> {
> union hv_ghcb *hv_ghcb;
> diff --git a/arch/x86/include/asm/mshyperv.h b/arch/x86/include/asm/mshyperv.h
> index f624d72b99d3..c8f66d269e5b 100644
> --- a/arch/x86/include/asm/mshyperv.h
> +++ b/arch/x86/include/asm/mshyperv.h
> @@ -274,6 +274,7 @@ void hv_sint_rdmsrl_ghcb(u64 msr, u64 *value);
> void hv_signal_eom_ghcb(void);
> void hv_ghcb_msr_write(u64 msr, u64 value);
> void hv_ghcb_msr_read(u64 msr, u64 *value);
> +u64 hv_ghcb_hypercall(u64 control, void *input, void *output, u32
> input_size);
>
> #define hv_get_synint_state_ghcb(int_num, val) \
> hv_sint_rdmsrl_ghcb(HV_X64_MSR_SINT0 + int_num, val)
> diff --git a/drivers/hv/connection.c b/drivers/hv/connection.c
> index c83612cddb99..79bca653dce9 100644
> --- a/drivers/hv/connection.c
> +++ b/drivers/hv/connection.c
> @@ -442,6 +442,10 @@ void vmbus_set_event(struct vmbus_channel *channel)
>
> ++channel->sig_events;
>
> - hv_do_fast_hypercall8(HVCALL_SIGNAL_EVENT, channel->sig_event);
> + if (hv_isolation_type_snp())
> + hv_ghcb_hypercall(HVCALL_SIGNAL_EVENT, >sig_event,
> + NULL, sizeof(u64));
> + else
> + hv_do_fast_hypercall8(HVCALL_SIGNAL_EVENT, channel->sig_event);
vmbus_set_event() is a hotpath so I'd suggest we introduce a static
branch instead of checking hv_isolation_type_snp() every time.
> }
> EXPORT_SYMBOL_GPL(vmbus_set_event);
> diff --git a/drivers/hv/hv.c b/drivers/hv/hv.c
> index 28e28ccc2081..6c64a7fd1ebd 100644
> --- a/drivers/hv/hv.c
> +++ b/drivers/hv/hv.c
> @@ -60,7 +60,13 @@ int
[RFC PATCH 5/12] HV: Add ghcb hvcall support for SNP VM
From: Tianyu Lan
Hyper-V provides ghcb hvcall to handle VMBus
HVCALL_SIGNAL_EVENT and HVCALL_POST_MESSAGE
msg in SNP Isolation VM. Add such support.
Signed-off-by: Tianyu Lan
---
arch/x86/hyperv/ivm.c | 69 +
arch/x86/include/asm/mshyperv.h | 1 +
drivers/hv/connection.c | 6 ++-
drivers/hv/hv.c | 8 +++-
4 files changed, 82 insertions(+), 2 deletions(-)
diff --git a/arch/x86/hyperv/ivm.c b/arch/x86/hyperv/ivm.c
index 4332bf7aaf9b..feaabcd151f5 100644
--- a/arch/x86/hyperv/ivm.c
+++ b/arch/x86/hyperv/ivm.c
@@ -14,8 +14,77 @@
union hv_ghcb {
struct ghcb ghcb;
+ struct {
+ u64 hypercalldata[509];
+ u64 outputgpa;
+ union {
+ union {
+ struct {
+ u32 callcode: 16;
+ u32 isfast : 1;
+ u32 reserved1 : 14;
+ u32 isnested: 1;
+ u32 countofelements : 12;
+ u32 reserved2 : 4;
+ u32 repstartindex : 12;
+ u32 reserved3 : 4;
+ };
+ u64 asuint64;
+ } hypercallinput;
+ union {
+ struct {
+ u16 callstatus;
+ u16 reserved1;
+ u32 elementsprocessed : 12;
+ u32 reserved2 : 20;
+ };
+ u64 asunit64;
+ } hypercalloutput;
+ };
+ u64 reserved2;
+ } hypercall;
} __packed __aligned(PAGE_SIZE);
+u64 hv_ghcb_hypercall(u64 control, void *input, void *output, u32 input_size)
+{
+ union hv_ghcb *hv_ghcb;
+ void **ghcb_base;
+ unsigned long flags;
+
+ if (!ms_hyperv.ghcb_base)
+ return -EFAULT;
+
+ local_irq_save(flags);
+ ghcb_base = (void **)this_cpu_ptr(ms_hyperv.ghcb_base);
+ hv_ghcb = (union hv_ghcb *)*ghcb_base;
+ if (!hv_ghcb) {
+ local_irq_restore(flags);
+ return -EFAULT;
+ }
+
+ memset(hv_ghcb, 0x00, HV_HYP_PAGE_SIZE);
+ hv_ghcb->ghcb.protocol_version = 1;
+ hv_ghcb->ghcb.ghcb_usage = 1;
+
+ hv_ghcb->hypercall.outputgpa = (u64)output;
+ hv_ghcb->hypercall.hypercallinput.asuint64 = 0;
+ hv_ghcb->hypercall.hypercallinput.callcode = control;
+
+ if (input_size)
+ memcpy(hv_ghcb->hypercall.hypercalldata, input, input_size);
+
+ VMGEXIT();
+
+ hv_ghcb->ghcb.ghcb_usage = 0x;
+ memset(hv_ghcb->ghcb.save.valid_bitmap, 0,
+ sizeof(hv_ghcb->ghcb.save.valid_bitmap));
+
+ local_irq_restore(flags);
+
+ return hv_ghcb->hypercall.hypercalloutput.callstatus;
+}
+EXPORT_SYMBOL_GPL(hv_ghcb_hypercall);
+
void hv_ghcb_msr_write(u64 msr, u64 value)
{
union hv_ghcb *hv_ghcb;
diff --git a/arch/x86/include/asm/mshyperv.h b/arch/x86/include/asm/mshyperv.h
index f624d72b99d3..c8f66d269e5b 100644
--- a/arch/x86/include/asm/mshyperv.h
+++ b/arch/x86/include/asm/mshyperv.h
@@ -274,6 +274,7 @@ void hv_sint_rdmsrl_ghcb(u64 msr, u64 *value);
void hv_signal_eom_ghcb(void);
void hv_ghcb_msr_write(u64 msr, u64 value);
void hv_ghcb_msr_read(u64 msr, u64 *value);
+u64 hv_ghcb_hypercall(u64 control, void *input, void *output, u32 input_size);
#define hv_get_synint_state_ghcb(int_num, val) \
hv_sint_rdmsrl_ghcb(HV_X64_MSR_SINT0 + int_num, val)
diff --git a/drivers/hv/connection.c b/drivers/hv/connection.c
index c83612cddb99..79bca653dce9 100644
--- a/drivers/hv/connection.c
+++ b/drivers/hv/connection.c
@@ -442,6 +442,10 @@ void vmbus_set_event(struct vmbus_channel *channel)
++channel->sig_events;
- hv_do_fast_hypercall8(HVCALL_SIGNAL_EVENT, channel->sig_event);
+ if (hv_isolation_type_snp())
+ hv_ghcb_hypercall(HVCALL_SIGNAL_EVENT, >sig_event,
+ NULL, sizeof(u64));
+ else
+ hv_do_fast_hypercall8(HVCALL_SIGNAL_EVENT, channel->sig_event);
}
EXPORT_SYMBOL_GPL(vmbus_set_event);
diff --git a/drivers/hv/hv.c b/drivers/hv/hv.c
index 28e28ccc2081..6c64a7fd1ebd 100644
--- a/drivers/hv/hv.c
+++ b/drivers/hv/hv.c
@@ -60,7 +60,13 @@ int hv_post_message(union hv_connection_id connection_id,
aligned_msg->payload_size = payload_size;
memcpy((void *)aligned_msg->payload, payload, payload_size);
- status = hv_do_hypercall(HVCALL_POST_MESSAGE, aligned_msg, NULL);
+ if (hv_isolation_type_snp())
+
