Commit 20c89a55 authored by Tianyu Lan's avatar Tianyu Lan Committed by Wei Liu
Browse files

x86/hyperv: Add ghcb hvcall support for SNP VM 



hyperv provides ghcb hvcall to handle VMBus
HVCALL_SIGNAL_EVENT and HVCALL_POST_MESSAGE
msg in SNP Isolation VM. Add such support.

Reviewed-by: default avatarMichael Kelley <mikelley@microsoft.com>
Signed-off-by: default avatarTianyu Lan <Tianyu.Lan@microsoft.com>
Link: https://lore.kernel.org/r/20211025122116.264793-8-ltykernel@gmail.com


Signed-off-by: default avatarWei Liu <wei.liu@kernel.org>
parent faff4406

arch/x86/hyperv/ivm.c

+75 −0
Original line number Diff line number Diff line
@@ -19,10 +19,85 @@ 
#include <asm/hypervisor.h>



#ifdef CONFIG_AMD_MEM_ENCRYPT



#define GHCB_USAGE_HYPERV_CALL	1



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(HV_HYP_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;

	u64 status;



	if (!hv_ghcb_pg)

		return -EFAULT;



	WARN_ON(in_nmi());



	local_irq_save(flags);

	ghcb_base = (void **)this_cpu_ptr(hv_ghcb_pg);

	hv_ghcb = (union hv_ghcb *)*ghcb_base;

	if (!hv_ghcb) {

		local_irq_restore(flags);

		return -EFAULT;

	}



	hv_ghcb->ghcb.protocol_version = GHCB_PROTOCOL_MAX;

	hv_ghcb->ghcb.ghcb_usage = GHCB_USAGE_HYPERV_CALL;



	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 = 0xffffffff;

	memset(hv_ghcb->ghcb.save.valid_bitmap, 0,

	       sizeof(hv_ghcb->ghcb.save.valid_bitmap));



	status = hv_ghcb->hypercall.hypercalloutput.callstatus;



	local_irq_restore(flags);



	return status;

}



void hv_ghcb_msr_write(u64 msr, u64 value)

{

	union hv_ghcb *hv_ghcb;

drivers/hv/connection.c

+5 −1
Original line number Diff line number Diff line
@@ -447,6 +447,10 @@ void vmbus_set_event(struct vmbus_channel *channel) 


	++channel->sig_events;



	if (hv_isolation_type_snp())

		hv_ghcb_hypercall(HVCALL_SIGNAL_EVENT, &channel->sig_event,

				NULL, sizeof(channel->sig_event));

	else

		hv_do_fast_hypercall8(HVCALL_SIGNAL_EVENT, channel->sig_event);

}

EXPORT_SYMBOL_GPL(vmbus_set_event);

drivers/hv/hv.c

+7 −1
Original line number Diff line number Diff line
@@ -98,7 +98,13 @@ 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())

		status = hv_ghcb_hypercall(HVCALL_POST_MESSAGE,

				(void *)aligned_msg, NULL,

				sizeof(*aligned_msg));

	else

		status = hv_do_hypercall(HVCALL_POST_MESSAGE,

				aligned_msg, NULL);



	/* Preemption must remain disabled until after the hypercall

	 * so some other thread can't get scheduled onto this cpu and

drivers/hv/hv_common.c

+6 −0
Original line number Diff line number Diff line
@@ -289,3 +289,9 @@ void __weak hyperv_cleanup(void) 
{

}

EXPORT_SYMBOL_GPL(hyperv_cleanup);



u64 __weak hv_ghcb_hypercall(u64 control, void *input, void *output, u32 input_size)

{

	return HV_STATUS_INVALID_PARAMETER;

}

EXPORT_SYMBOL_GPL(hv_ghcb_hypercall);

include/asm-generic/mshyperv.h

+1 −0
Original line number Diff line number Diff line
@@ -266,6 +266,7 @@ bool hv_is_hibernation_supported(void); 
enum hv_isolation_type hv_get_isolation_type(void);

bool hv_is_isolation_supported(void);

bool hv_isolation_type_snp(void);

u64 hv_ghcb_hypercall(u64 control, void *input, void *output, u32 input_size);

void hyperv_cleanup(void);

bool hv_query_ext_cap(u64 cap_query);

#else /* CONFIG_HYPERV */