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[16/18] KVM: doc: Add API documentation on the KVM_REG_ARM_WORKAROUNDS register

Message ID 20190709122507.214494-17-marc.zyngier@arm.com (mailing list archive)
State New, archived
Headers show
Series [GIT,PULL] KVM/arm updates for Linux 5.3 | expand

Commit Message

Marc Zyngier July 9, 2019, 12:25 p.m. UTC 
From: Andre Przywara <andre.przywara@arm.com>

Add documentation for the newly defined firmware registers to save and
restore any vulnerability mitigation status.

Signed-off-by: Andre Przywara <andre.przywara@arm.com>
Reviewed-by: Steven Price <steven.price@arm.com>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
---
 Documentation/virtual/kvm/arm/psci.txt | 31 ++++++++++++++++++++++++++
 1 file changed, 31 insertions(+)
diff mbox series

Patch

diff --git a/Documentation/virtual/kvm/arm/psci.txt b/Documentation/virtual/kvm/arm/psci.txt
index aafdab887b04..559586fc9d37 100644
--- a/Documentation/virtual/kvm/arm/psci.txt
+++ b/Documentation/virtual/kvm/arm/psci.txt
@@ -28,3 +28,34 @@  The following register is defined:
   - 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