From cec0e48be339f06879d971702f206e9683956ef1 Mon Sep 17 00:00:00 2001 From: Mauro Carvalho Chehab Date: Mon, 10 Feb 2020 07:02:57 +0100 Subject: docs: kvm: arm/psci.txt: convert to ReST - Add a title for the document; - Adjust whitespaces for it to be properly formatted after parsed. Signed-off-by: Mauro Carvalho Chehab Signed-off-by: Paolo Bonzini --- Documentation/virt/kvm/arm/index.rst | 1 + Documentation/virt/kvm/arm/psci.rst | 77 ++++++++++++++++++++++++++++++++++++ Documentation/virt/kvm/arm/psci.txt | 61 ---------------------------- 3 files changed, 78 insertions(+), 61 deletions(-) create mode 100644 Documentation/virt/kvm/arm/psci.rst delete mode 100644 Documentation/virt/kvm/arm/psci.txt (limited to 'Documentation') diff --git a/Documentation/virt/kvm/arm/index.rst b/Documentation/virt/kvm/arm/index.rst index 134fa5fa77e5..3e2b2aba90fc 100644 --- a/Documentation/virt/kvm/arm/index.rst +++ b/Documentation/virt/kvm/arm/index.rst @@ -8,4 +8,5 @@ ARM :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 000000000000..d52c2e83b5b8 --- /dev/null +++ b/Documentation/virt/kvm/arm/psci.rst @@ -0,0 +1,77 @@ +.. 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/psci.txt b/Documentation/virt/kvm/arm/psci.txt deleted file mode 100644 index 559586fc9d37..000000000000 --- a/Documentation/virt/kvm/arm/psci.txt +++ /dev/null @@ -1,61 +0,0 @@ -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 -- cgit