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KVM: arm64: Specify hypercall ABI for retrieving target implementations

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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: Oliver Upton <oliver.upton@linux.dev>
Suggested-by: Marc Zyngier <maz@kernel.org>
Reviewed-by: Cornelia Huck <cohuck@redhat.com>
Reviewed-by: Sebastian Ott <sebott@redhat.com>
Signed-off-by: Shameer Kolothum <shameerali.kolothum.thodi@huawei.com>
Link: https://lore.kernel.org/r/20250221140229.12588-3-shameerali.kolothum.thodi@huawei.com
Signed-off-by: Oliver Upton <oliver.upton@linux.dev>
This commit is contained in:
Shameer Kolothum
2025-02-21 14:02:25 +00:00
committed by Oliver Upton
parent e3121298c7
commit 57e5cc9b8a
2 changed files with 74 additions and 0 deletions
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59
Documentation/virt/kvm/arm/hypercalls.rst
View File

@@ -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 |
+---------------------+----------+----+---------------------------------------------+

15
include/linux/arm-smccc.h
View File

@@ -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