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authorShameer Kolothum <shameerali.kolothum.thodi@huawei.com>2025-02-21 14:02:25 +0000
committerOliver Upton <oliver.upton@linux.dev>2025-02-26 13:30:18 -0800
commit57e5cc9b8a399f85c95b6249ecb423553aad209c (patch)
treef750aa72f9eba538530ea8d2dd3e136864909f37
parente3121298c7fcaf488df8e61f50fced9a741c4c44 (diff)
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: 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>
-rw-r--r--Documentation/virt/kvm/arm/hypercalls.rst59
-rw-r--r--include/linux/arm-smccc.h15
2 files changed, 74 insertions, 0 deletions
diff --git a/Documentation/virt/kvm/arm/hypercalls.rst b/Documentation/virt/kvm/arm/hypercalls.rst
index af7bc2c2e0cb..7400a89aabf8 100644
--- a/Documentation/virt/kvm/arm/hypercalls.rst
+++ b/Documentation/virt/kvm/arm/hypercalls.rst
@@ -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 |
++---------------------+----------+----+---------------------------------------------+
diff --git a/include/linux/arm-smccc.h b/include/linux/arm-smccc.h
index 67f6fdf2e7cd..f19be5754090 100644
--- a/include/linux/arm-smccc.h
+++ b/include/linux/arm-smccc.h
@@ -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