summaryrefslogtreecommitdiffstats
path: root/Documentation/virtual
diff options
context:
space:
mode:
authorChristoffer Dall <cdall@linaro.org>2017-05-02 20:19:15 +0200
committerChristoffer Dall <cdall@linaro.org>2017-06-08 16:59:57 +0200
commit99a1db7a2c9b2ecb9a801cee3f6a7a71945a2fca (patch)
tree8364ac9261a8c86c41a8b90410dbdc9b56093404 /Documentation/virtual
parent85e69ad7f2cc6dd829987a70cf32785b1d8c8b27 (diff)
downloadlinux-99a1db7a2c9b2ecb9a801cee3f6a7a71945a2fca.tar.bz2
KVM: arm/arm64: Allow setting the timer IRQ numbers from userspace
First we define an ABI using the vcpu devices that lets userspace set the interrupt numbers for the various timers on both the 32-bit and 64-bit KVM/ARM implementations. Second, we add the definitions for the groups and attributes introduced by the above ABI. (We add the PMU define on the 32-bit side as well for symmetry and it may get used some day.) Third, we set up the arch-specific vcpu device operation handlers to call into the timer code for anything related to the KVM_ARM_VCPU_TIMER_CTRL group. Fourth, we implement support for getting and setting the timer interrupt numbers using the above defined ABI in the arch timer code. Fifth, we introduce error checking upon enabling the arch timer (which is called when first running a VCPU) to check that all VCPUs are configured to use the same PPI for the timer (as mandated by the architecture) and that the virtual and physical timers are not configured to use the same IRQ number. Signed-off-by: Christoffer Dall <cdall@linaro.org> Reviewed-by: Marc Zyngier <marc.zyngier@arm.com>
Diffstat (limited to 'Documentation/virtual')
-rw-r--r--Documentation/virtual/kvm/devices/vcpu.txt25
1 files changed, 25 insertions, 0 deletions
diff --git a/Documentation/virtual/kvm/devices/vcpu.txt b/Documentation/virtual/kvm/devices/vcpu.txt
index d7236a3e01dc..2b5dab16c4f2 100644
--- a/Documentation/virtual/kvm/devices/vcpu.txt
+++ b/Documentation/virtual/kvm/devices/vcpu.txt
@@ -35,3 +35,28 @@ Returns: -ENODEV: PMUv3 not supported or GIC not initialized
Request the initialization of the PMUv3. If using the PMUv3 with an in-kernel
virtual GIC implementation, this must be done after initializing the in-kernel
irqchip.
+
+
+2. GROUP: KVM_ARM_VCPU_TIMER_CTRL
+Architectures: ARM,ARM64
+
+2.1. ATTRIBUTE: KVM_ARM_VCPU_TIMER_IRQ_VTIMER
+2.2. ATTRIBUTE: KVM_ARM_VCPU_TIMER_IRQ_PTIMER
+Parameters: in kvm_device_attr.addr the address for the timer interrupt is a
+ pointer to an int
+Returns: -EINVAL: Invalid timer interrupt number
+ -EBUSY: One or more VCPUs has already run
+
+A value describing the architected timer interrupt number when connected to an
+in-kernel virtual GIC. These must be a PPI (16 <= intid < 32). Setting the
+attribute overrides the default values (see below).
+
+KVM_ARM_VCPU_TIMER_IRQ_VTIMER: The EL1 virtual timer intid (default: 27)
+KVM_ARM_VCPU_TIMER_IRQ_PTIMER: The EL1 physical timer intid (default: 30)
+
+Setting the same PPI for different timers will prevent the VCPUs from running.
+Setting the interrupt number on a VCPU configures all VCPUs created at that
+time to use the number provided for a given timer, overwriting any previously
+configured values on other VCPUs. Userspace should configure the interrupt
+numbers on at least one VCPU after creating all VCPUs and before running any
+VCPUs.