Commit 57e5cc9b authored by Shameer Kolothum's avatar Shameer Kolothum Committed by Oliver Upton
Browse files

KVM: arm64: Specify hypercall ABI for retrieving target implementations 



If the Guest requires migration to multiple targets, these hypercalls
will provide a way to retrieve the target CPU implementations from
the user space VMM.

Subsequent patch will use this to enable the associated errata.

Suggested-by: default avatarOliver Upton <oliver.upton@linux.dev>
Suggested-by: default avatarMarc Zyngier <maz@kernel.org>
Reviewed-by: default avatarCornelia Huck <cohuck@redhat.com>
Reviewed-by: default avatarSebastian Ott <sebott@redhat.com>
Signed-off-by: default avatarShameer Kolothum <shameerali.kolothum.thodi@huawei.com>
Link: https://lore.kernel.org/r/20250221140229.12588-3-shameerali.kolothum.thodi@huawei.com


Signed-off-by: default avatarOliver Upton <oliver.upton@linux.dev>
parent e3121298

Documentation/virt/kvm/arm/hypercalls.rst

+59 −0
Original line number Diff line number Diff line
@@ -142,3 +142,62 @@ region is equal to the memory protection granule advertised by 
|                     |          |    +---------------------------------------------+

|                     |          |    | ``INVALID_PARAMETER (-3)``                  |

+---------------------+----------+----+---------------------------------------------+



``ARM_SMCCC_VENDOR_HYP_KVM_DISCOVER_IMPL_VER_FUNC_ID``

-------------------------------------------------------

Request the target CPU implementation version information and the number of target

implementations for the Guest VM.



+---------------------+-------------------------------------------------------------+

| Presence:           | Optional;  KVM/ARM64 Guests only                            |

+---------------------+-------------------------------------------------------------+

| Calling convention: | HVC64                                                       |

+---------------------+----------+--------------------------------------------------+

| Function ID:        | (uint32) | 0xC6000040                                       |

+---------------------+----------+--------------------------------------------------+

| Arguments:          | None                                                        |

+---------------------+----------+----+---------------------------------------------+

| Return Values:      | (int64)  | R0 | ``SUCCESS (0)``                             |

|                     |          |    +---------------------------------------------+

|                     |          |    | ``NOT_SUPPORTED (-1)``                      |

|                     +----------+----+---------------------------------------------+

|                     | (uint64) | R1 | Bits [63:32] Reserved/Must be zero          |

|                     |          |    +---------------------------------------------+

|                     |          |    | Bits [31:16] Major version                  |

|                     |          |    +---------------------------------------------+

|                     |          |    | Bits [15:0] Minor version                   |

|                     +----------+----+---------------------------------------------+

|                     | (uint64) | R2 | Number of target implementations            |

|                     +----------+----+---------------------------------------------+

|                     | (uint64) | R3 | Reserved / Must be zero                     |

+---------------------+----------+----+---------------------------------------------+



``ARM_SMCCC_VENDOR_HYP_KVM_DISCOVER_IMPL_CPUS_FUNC_ID``

-------------------------------------------------------



Request the target CPU implementation information for the Guest VM. The Guest kernel

will use this information to enable the associated errata.



+---------------------+-------------------------------------------------------------+

| Presence:           | Optional;  KVM/ARM64 Guests only                            |

+---------------------+-------------------------------------------------------------+

| Calling convention: | HVC64                                                       |

+---------------------+----------+--------------------------------------------------+

| Function ID:        | (uint32) | 0xC6000041                                       |

+---------------------+----------+----+---------------------------------------------+

| Arguments:          | (uint64) | R1 | selected implementation index               |

|                     +----------+----+---------------------------------------------+

|                     | (uint64) | R2 | Reserved / Must be zero                     |

|                     +----------+----+---------------------------------------------+

|                     | (uint64) | R3 | Reserved / Must be zero                     |

+---------------------+----------+----+---------------------------------------------+

| Return Values:      | (int64)  | R0 | ``SUCCESS (0)``                             |

|                     |          |    +---------------------------------------------+

|                     |          |    | ``INVALID_PARAMETER (-3)``                  |

|                     +----------+----+---------------------------------------------+

|                     | (uint64) | R1 | MIDR_EL1 of the selected implementation     |

|                     +----------+----+---------------------------------------------+

|                     | (uint64) | R2 | REVIDR_EL1 of the selected implementation   |

|                     +----------+----+---------------------------------------------+

|                     | (uint64) | R3 | AIDR_EL1  of the selected implementation    |

+---------------------+----------+----+---------------------------------------------+

include/linux/arm-smccc.h

+15 −0
Original line number Diff line number Diff line
@@ -179,6 +179,9 @@ 
#define ARM_SMCCC_KVM_FUNC_PKVM_RESV_62		62

#define ARM_SMCCC_KVM_FUNC_PKVM_RESV_63		63

/* End of pKVM hypercall range */

#define ARM_SMCCC_KVM_FUNC_DISCOVER_IMPL_VER	64

#define ARM_SMCCC_KVM_FUNC_DISCOVER_IMPL_CPUS	65



#define ARM_SMCCC_KVM_FUNC_FEATURES_2		127

#define ARM_SMCCC_KVM_NUM_FUNCS			128
@@ -225,6 +228,18 @@ 
			   ARM_SMCCC_OWNER_VENDOR_HYP,			\

			   ARM_SMCCC_KVM_FUNC_MMIO_GUARD)



#define ARM_SMCCC_VENDOR_HYP_KVM_DISCOVER_IMPL_VER_FUNC_ID		\

	ARM_SMCCC_CALL_VAL(ARM_SMCCC_FAST_CALL,				\

			   ARM_SMCCC_SMC_64,				\

			   ARM_SMCCC_OWNER_VENDOR_HYP,			\

			   ARM_SMCCC_KVM_FUNC_DISCOVER_IMPL_VER)



#define ARM_SMCCC_VENDOR_HYP_KVM_DISCOVER_IMPL_CPUS_FUNC_ID		\

	ARM_SMCCC_CALL_VAL(ARM_SMCCC_FAST_CALL,				\

			   ARM_SMCCC_SMC_64,				\

			   ARM_SMCCC_OWNER_VENDOR_HYP,			\

			   ARM_SMCCC_KVM_FUNC_DISCOVER_IMPL_CPUS)



/* ptp_kvm counter type ID */

#define KVM_PTP_VIRT_COUNTER			0

#define KVM_PTP_PHYS_COUNTER			1