Adding upstream version 5.10.209.upstream/5.10.209upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

4 files changed, 237 insertions, 0 deletions

diff --git a/Documentation/virt/kvm/arm/hyp-abi.rst b/Documentation/virt/kvm/arm/hyp-abi.rst
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+.. SPDX-License-Identifier: GPL-2.0
+
+=======================================
+Internal ABI between the kernel and HYP
+=======================================
+
+This file documents the interaction between the Linux kernel and the
+hypervisor layer when running Linux as a hypervisor (for example
+KVM). It doesn't cover the interaction of the kernel with the
+hypervisor when running as a guest (under Xen, KVM or any other
+hypervisor), or any hypervisor-specific interaction when the kernel is
+used as a host.
+
+Note: KVM/arm has been removed from the kernel. The API described
+here is still valid though, as it allows the kernel to kexec when
+booted at HYP. It can also be used by a hypervisor other than KVM
+if necessary.
+
+On arm and arm64 (without VHE), the kernel doesn't run in hypervisor
+mode, but still needs to interact with it, allowing a built-in
+hypervisor to be either installed or torn down.
+
+In order to achieve this, the kernel must be booted at HYP (arm) or
+EL2 (arm64), allowing it to install a set of stubs before dropping to
+SVC/EL1. These stubs are accessible by using a 'hvc #0' instruction,
+and only act on individual CPUs.
+
+Unless specified otherwise, any built-in hypervisor must implement
+these functions (see arch/arm{,64}/include/asm/virt.h):
+
+* ::
+
+    r0/x0 = HVC_SET_VECTORS
+    r1/x1 = vectors
+
+  Set HVBAR/VBAR_EL2 to 'vectors' to enable a hypervisor. 'vectors'
+  must be a physical address, and respect the alignment requirements
+  of the architecture. Only implemented by the initial stubs, not by
+  Linux hypervisors.
+
+* ::
+
+    r0/x0 = HVC_RESET_VECTORS
+
+  Turn HYP/EL2 MMU off, and reset HVBAR/VBAR_EL2 to the initials
+  stubs' exception vector value. This effectively disables an existing
+  hypervisor.
+
+* ::
+
+    r0/x0 = HVC_SOFT_RESTART
+    r1/x1 = restart address
+    x2 = x0's value when entering the next payload (arm64)
+    x3 = x1's value when entering the next payload (arm64)
+    x4 = x2's value when entering the next payload (arm64)
+
+  Mask all exceptions, disable the MMU, clear I+D bits, move the arguments
+  into place (arm64 only), and jump to the restart address while at HYP/EL2.
+  This hypercall is not expected to return to its caller.
+
+Any other value of r0/x0 triggers a hypervisor-specific handling,
+which is not documented here.
+
+The return value of a stub hypercall is held by r0/x0, and is 0 on
+success, and HVC_STUB_ERR on error. A stub hypercall is allowed to
+clobber any of the caller-saved registers (x0-x18 on arm64, r0-r3 and
+ip on arm). It is thus recommended to use a function call to perform
+the hypercall.
diff --git a/Documentation/virt/kvm/arm/index.rst b/Documentation/virt/kvm/arm/index.rst
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+.. SPDX-License-Identifier: GPL-2.0
+
+===
+ARM
+===
+
+.. toctree::
+   :maxdepth: 2
+
+   hyp-abi
+   psci
+   pvtime
diff --git a/Documentation/virt/kvm/arm/psci.rst b/Documentation/virt/kvm/arm/psci.rst
new file mode 100644
index 000000000..d52c2e83b
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+++ b/Documentation/virt/kvm/arm/psci.rst
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+.. SPDX-License-Identifier: GPL-2.0
+
+=========================================
+Power State Coordination Interface (PSCI)
+=========================================
+
+KVM implements the PSCI (Power State Coordination Interface)
+specification in order to provide services such as CPU on/off, reset
+and power-off to the guest.
+
+The PSCI specification is regularly updated to provide new features,
+and KVM implements these updates if they make sense from a virtualization
+point of view.
+
+This means that a guest booted on two different versions of KVM can
+observe two different "firmware" revisions. This could cause issues if
+a given guest is tied to a particular PSCI revision (unlikely), or if
+a migration causes a different PSCI version to be exposed out of the
+blue to an unsuspecting guest.
+
+In order to remedy this situation, KVM exposes a set of "firmware
+pseudo-registers" that can be manipulated using the GET/SET_ONE_REG
+interface. These registers can be saved/restored by userspace, and set
+to a convenient value if required.
+
+The following register is defined:
+
+* KVM_REG_ARM_PSCI_VERSION:
+
+  - Only valid if the vcpu has the KVM_ARM_VCPU_PSCI_0_2 feature set
+    (and thus has already been initialized)
+  - Returns the current PSCI version on GET_ONE_REG (defaulting to the
+    highest PSCI version implemented by KVM and compatible with v0.2)
+  - Allows any PSCI version implemented by KVM and compatible with
+    v0.2 to be set with SET_ONE_REG
+  - Affects the whole VM (even if the register view is per-vcpu)
+
+* KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_1:
+    Holds the state of the firmware support to mitigate CVE-2017-5715, as
+    offered by KVM to the guest via a HVC call. The workaround is described
+    under SMCCC_ARCH_WORKAROUND_1 in [1].
+
+  Accepted values are:
+
+    KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_1_NOT_AVAIL:
+      KVM does not offer
+      firmware support for the workaround. The mitigation status for the
+      guest is unknown.
+    KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_1_AVAIL:
+      The workaround HVC call is
+      available to the guest and required for the mitigation.
+    KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_1_NOT_REQUIRED:
+      The workaround HVC call
+      is available to the guest, but it is not needed on this VCPU.
+
+* KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_2:
+    Holds the state of the firmware support to mitigate CVE-2018-3639, as
+    offered by KVM to the guest via a HVC call. The workaround is described
+    under SMCCC_ARCH_WORKAROUND_2 in [1]_.
+
+  Accepted values are:
+
+    KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_2_NOT_AVAIL:
+      A workaround is not
+      available. KVM does not offer firmware support for the workaround.
+    KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_2_UNKNOWN:
+      The workaround state is
+      unknown. KVM does not offer firmware support for the workaround.
+    KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_2_AVAIL:
+      The workaround is available,
+      and can be disabled by a vCPU. If
+      KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_2_ENABLED is set, it is active for
+      this vCPU.
+    KVM_REG_ARM_SMCCC_ARCH_WORKAROUND_2_NOT_REQUIRED:
+      The workaround is always active on this vCPU or it is not needed.
+
+.. [1] https://developer.arm.com/-/media/developer/pdf/ARM_DEN_0070A_Firmware_interfaces_for_mitigating_CVE-2017-5715.pdf
diff --git a/Documentation/virt/kvm/arm/pvtime.rst b/Documentation/virt/kvm/arm/pvtime.rst
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index 000000000..687b60d76
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+++ b/Documentation/virt/kvm/arm/pvtime.rst
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+.. SPDX-License-Identifier: GPL-2.0
+
+Paravirtualized time support for arm64
+======================================
+
+Arm specification DEN0057/A defines a standard for paravirtualised time
+support for AArch64 guests:
+
+https://developer.arm.com/docs/den0057/a
+
+KVM/arm64 implements the stolen time part of this specification by providing
+some hypervisor service calls to support a paravirtualized guest obtaining a
+view of the amount of time stolen from its execution.
+
+Two new SMCCC compatible hypercalls are defined:
+
+* PV_TIME_FEATURES: 0xC5000020
+* PV_TIME_ST:       0xC5000021
+
+These are only available in the SMC64/HVC64 calling convention as
+paravirtualized time is not available to 32 bit Arm guests. The existence of
+the PV_FEATURES hypercall should be probed using the SMCCC 1.1 ARCH_FEATURES
+mechanism before calling it.
+
+PV_TIME_FEATURES
+    ============= ========    ==========
+    Function ID:  (uint32)    0xC5000020
+    PV_call_id:   (uint32)    The function to query for support.
+                              Currently only PV_TIME_ST is supported.
+    Return value: (int64)     NOT_SUPPORTED (-1) or SUCCESS (0) if the relevant
+                              PV-time feature is supported by the hypervisor.
+    ============= ========    ==========
+
+PV_TIME_ST
+    ============= ========    ==========
+    Function ID:  (uint32)    0xC5000021
+    Return value: (int64)     IPA of the stolen time data structure for this
+                              VCPU. On failure:
+                              NOT_SUPPORTED (-1)
+    ============= ========    ==========
+
+The IPA returned by PV_TIME_ST should be mapped by the guest as normal memory
+with inner and outer write back caching attributes, in the inner shareable
+domain. A total of 16 bytes from the IPA returned are guaranteed to be
+meaningfully filled by the hypervisor (see structure below).
+
+PV_TIME_ST returns the structure for the calling VCPU.
+
+Stolen Time
+-----------
+
+The structure pointed to by the PV_TIME_ST hypercall is as follows:
+
++-------------+-------------+-------------+----------------------------+
+| Field       | Byte Length | Byte Offset | Description                |
++=============+=============+=============+============================+
+| Revision    |      4      |      0      | Must be 0 for version 1.0  |
++-------------+-------------+-------------+----------------------------+
+| Attributes  |      4      |      4      | Must be 0                  |
++-------------+-------------+-------------+----------------------------+
+| Stolen time |      8      |      8      | Stolen time in unsigned    |
+|             |             |             | nanoseconds indicating how |
+|             |             |             | much time this VCPU thread |
+|             |             |             | was involuntarily not      |
+|             |             |             | running on a physical CPU. |
++-------------+-------------+-------------+----------------------------+
+
+All values in the structure are stored little-endian.
+
+The structure will be updated by the hypervisor prior to scheduling a VCPU. It
+will be present within a reserved region of the normal memory given to the
+guest. The guest should not attempt to write into this memory. There is a
+structure per VCPU of the guest.
+
+It is advisable that one or more 64k pages are set aside for the purpose of
+these structures and not used for other purposes, this enables the guest to map
+the region using 64k pages and avoids conflicting attributes with other memory.
+
+For the user space interface see Documentation/virt/kvm/devices/vcpu.rst
+section "3. GROUP: KVM_ARM_VCPU_PVTIME_CTRL".