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| author | Oliver Upton <oliver.upton@linux.dev> | 2025-03-19 14:53:09 -0700 |
|---|---|---|
| committer | Oliver Upton <oliver.upton@linux.dev> | 2025-03-19 14:53:16 -0700 |
| commit | d300b0168ea8fd5022a1413bd37ab63f4e5a7d4d (patch) | |
| tree | aa9e431f8b5db99e1a3c70dcec6c451108f1c62a /Documentation/virt | |
| parent | 13f64f6d215ca229a615ef26cf452e38e22f4cdb (diff) | |
| parent | 44ff44cadbd144ee1159f5687a852c49c4290262 (diff) | |
| download | ath-d300b0168ea8fd5022a1413bd37ab63f4e5a7d4d.tar.gz | |
Merge branch 'kvm-arm64/pv-cpuid' into kvmarm/next
* kvm-arm64/pv-cpuid:
: Paravirtualized implementation ID, courtesy of Shameer Kolothum
:
: Big-little has historically been a pain in the ass to virtualize. The
: implementation ID (MIDR, REVIDR, AIDR) of a vCPU can change at the whim
: of vCPU scheduling. This can be particularly annoying when the guest
: needs to know the underlying implementation to mitigate errata.
:
: "Hyperscalers" face a similar scheduling problem, where VMs may freely
: migrate between hosts in a pool of heterogenous hardware. And yes, our
: server-class friends are equally riddled with errata too.
:
: In absence of an architected solution to this wart on the ecosystem,
: introduce support for paravirtualizing the implementation exposed
: to a VM, allowing the VMM to describe the pool of implementations that a
: VM may be exposed to due to scheduling/migration.
:
: Userspace is expected to intercept and handle these hypercalls using the
: SMCCC filter UAPI, should it choose to do so.
smccc: kvm_guest: Fix kernel builds for 32 bit arm
KVM: selftests: Add test for KVM_REG_ARM_VENDOR_HYP_BMAP_2
smccc/kvm_guest: Enable errata based on implementation CPUs
arm64: Make _midr_in_range_list() an exported function
KVM: arm64: Introduce KVM_REG_ARM_VENDOR_HYP_BMAP_2
KVM: arm64: Specify hypercall ABI for retrieving target implementations
arm64: Modify _midr_range() functions to read MIDR/REVIDR internally
Signed-off-by: Oliver Upton <oliver.upton@linux.dev>
Diffstat (limited to 'Documentation/virt')
| -rw-r--r-- | Documentation/virt/kvm/arm/fw-pseudo-registers.rst | 15 | ||||
| -rw-r--r-- | Documentation/virt/kvm/arm/hypercalls.rst | 59 |
2 files changed, 73 insertions, 1 deletions
diff --git a/Documentation/virt/kvm/arm/fw-pseudo-registers.rst b/Documentation/virt/kvm/arm/fw-pseudo-registers.rst index b90fd0b0fa666..d78b53b05dfcf 100644 --- a/Documentation/virt/kvm/arm/fw-pseudo-registers.rst +++ b/Documentation/virt/kvm/arm/fw-pseudo-registers.rst @@ -116,7 +116,7 @@ The pseudo-firmware bitmap register are as follows: ARM DEN0057A. * KVM_REG_ARM_VENDOR_HYP_BMAP: - Controls the bitmap of the Vendor specific Hypervisor Service Calls. + Controls the bitmap of the Vendor specific Hypervisor Service Calls[0-63]. The following bits are accepted: @@ -127,6 +127,19 @@ The pseudo-firmware bitmap register are as follows: Bit-1: KVM_REG_ARM_VENDOR_HYP_BIT_PTP: The bit represents the Precision Time Protocol KVM service. +* KVM_REG_ARM_VENDOR_HYP_BMAP_2: + Controls the bitmap of the Vendor specific Hypervisor Service Calls[64-127]. + + The following bits are accepted: + + Bit-0: KVM_REG_ARM_VENDOR_HYP_BIT_DISCOVER_IMPL_VER + This represents the ARM_SMCCC_VENDOR_HYP_KVM_DISCOVER_IMPL_VER_FUNC_ID + function-id. This is reset to 0. + + Bit-1: KVM_REG_ARM_VENDOR_HYP_BIT_DISCOVER_IMPL_CPUS + This represents the ARM_SMCCC_VENDOR_HYP_KVM_DISCOVER_IMPL_CPUS_FUNC_ID + function-id. This is reset to 0. + Errors: ======= ============================================================= diff --git a/Documentation/virt/kvm/arm/hypercalls.rst b/Documentation/virt/kvm/arm/hypercalls.rst index af7bc2c2e0cb4..7400a89aabf88 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 | ++---------------------+----------+----+---------------------------------------------+ |