From 327432c2469e0069679009886556d15eeddeb0cc Mon Sep 17 00:00:00 2001 From: Christoffer Dall Date: Mon, 16 Jul 2018 15:06:27 +0200 Subject: KVM: arm/arm64: vgic: Update documentation of the GIC devices wrt IIDR Update the documentation to reflect the ordering requirements of restoring the GICD_IIDR register before any other registers and the effects this has on restoring the interrupt groups for an emulated GICv2 instance. Also remove some outdated limitations in the documentation while we're at it. Reviewed-by: Andrew Jones Signed-off-by: Christoffer Dall Signed-off-by: Marc Zyngier --- Documentation/virtual/kvm/devices/arm-vgic-v3.txt | 8 ++++++++ Documentation/virtual/kvm/devices/arm-vgic.txt | 15 +++++++++------ 2 files changed, 17 insertions(+), 6 deletions(-) (limited to 'Documentation/virtual') diff --git a/Documentation/virtual/kvm/devices/arm-vgic-v3.txt b/Documentation/virtual/kvm/devices/arm-vgic-v3.txt index 2408ab720ef7..ff290b43c8e5 100644 --- a/Documentation/virtual/kvm/devices/arm-vgic-v3.txt +++ b/Documentation/virtual/kvm/devices/arm-vgic-v3.txt @@ -100,6 +100,14 @@ Groups: Note that distributor fields are not banked, but return the same value regardless of the mpidr used to access the register. + GICD_IIDR.Revision is updated when the KVM implementation is changed in a + way directly observable by the guest or userspace. Userspace should read + GICD_IIDR from KVM and write back the read value to confirm its expected + behavior is aligned with the KVM implementation. Userspace should set + GICD_IIDR before setting any other registers to ensure the expected + behavior. + + The GICD_STATUSR and GICR_STATUSR registers are architecturally defined such that a write of a clear bit has no effect, whereas a write with a set bit clears that value. To allow userspace to freely set the values of these two diff --git a/Documentation/virtual/kvm/devices/arm-vgic.txt b/Documentation/virtual/kvm/devices/arm-vgic.txt index b3ce12643553..97b6518148f8 100644 --- a/Documentation/virtual/kvm/devices/arm-vgic.txt +++ b/Documentation/virtual/kvm/devices/arm-vgic.txt @@ -49,9 +49,15 @@ Groups: index is specified with the vcpu_index field. Note that most distributor fields are not banked, but return the same value regardless of the vcpu_index used to access the register. - Limitations: - - Priorities are not implemented, and registers are RAZ/WI - - Currently only implemented for KVM_DEV_TYPE_ARM_VGIC_V2. + + GICD_IIDR.Revision is updated when the KVM implementation of an emulated + GICv2 is changed in a way directly observable by the guest or userspace. + Userspace should read GICD_IIDR from KVM and write back the read value to + confirm its expected behavior is aligned with the KVM implementation. + Userspace should set GICD_IIDR before setting any other registers (both + KVM_DEV_ARM_VGIC_GRP_DIST_REGS and KVM_DEV_ARM_VGIC_GRP_CPU_REGS) to ensure + the expected behavior. Unless GICD_IIDR has been set from userspace, writes + to the interrupt group registers (GICD_IGROUPR) are ignored. Errors: -ENXIO: Getting or setting this register is not yet supported -EBUSY: One or more VCPUs are running @@ -94,9 +100,6 @@ Groups: use the lower 5 bits to communicate with the KVM device and must shift the value left by 3 places to obtain the actual priority mask level. - Limitations: - - Priorities are not implemented, and registers are RAZ/WI - - Currently only implemented for KVM_DEV_TYPE_ARM_VGIC_V2. Errors: -ENXIO: Getting or setting this register is not yet supported -EBUSY: One or more VCPUs are running -- cgit v1.2.1 From b7b27facc7b50a5fce0afaa3df56157136ce181a Mon Sep 17 00:00:00 2001 From: Dongjiu Geng Date: Thu, 19 Jul 2018 16:24:22 +0100 Subject: arm/arm64: KVM: Add KVM_GET/SET_VCPU_EVENTS For the migrating VMs, user space may need to know the exception state. For example, in the machine A, KVM make an SError pending, when migrate to B, KVM also needs to pend an SError. This new IOCTL exports user-invisible states related to SError. Together with appropriate user space changes, user space can get/set the SError exception state to do migrate/snapshot/suspend. Signed-off-by: Dongjiu Geng Reviewed-by: James Morse [expanded documentation wording] Signed-off-by: James Morse Signed-off-by: Marc Zyngier --- Documentation/virtual/kvm/api.txt | 54 ++++++++++++++++++++++++++++++++++++--- 1 file changed, 50 insertions(+), 4 deletions(-) (limited to 'Documentation/virtual') diff --git a/Documentation/virtual/kvm/api.txt b/Documentation/virtual/kvm/api.txt index d10944e619d3..284d36e72f28 100644 --- a/Documentation/virtual/kvm/api.txt +++ b/Documentation/virtual/kvm/api.txt @@ -835,11 +835,13 @@ struct kvm_clock_data { Capability: KVM_CAP_VCPU_EVENTS Extended by: KVM_CAP_INTR_SHADOW -Architectures: x86 -Type: vm ioctl +Architectures: x86, arm64 +Type: vcpu ioctl Parameters: struct kvm_vcpu_event (out) Returns: 0 on success, -1 on error +X86: + Gets currently pending exceptions, interrupts, and NMIs as well as related states of the vcpu. @@ -881,15 +883,52 @@ Only two fields are defined in the flags field: - KVM_VCPUEVENT_VALID_SMM may be set in the flags field to signal that smi contains a valid state. +ARM64: + +If the guest accesses a device that is being emulated by the host kernel in +such a way that a real device would generate a physical SError, KVM may make +a virtual SError pending for that VCPU. This system error interrupt remains +pending until the guest takes the exception by unmasking PSTATE.A. + +Running the VCPU may cause it to take a pending SError, or make an access that +causes an SError to become pending. The event's description is only valid while +the VPCU is not running. + +This API provides a way to read and write the pending 'event' state that is not +visible to the guest. To save, restore or migrate a VCPU the struct representing +the state can be read then written using this GET/SET API, along with the other +guest-visible registers. It is not possible to 'cancel' an SError that has been +made pending. + +A device being emulated in user-space may also wish to generate an SError. To do +this the events structure can be populated by user-space. The current state +should be read first, to ensure no existing SError is pending. If an existing +SError is pending, the architecture's 'Multiple SError interrupts' rules should +be followed. (2.5.3 of DDI0587.a "ARM Reliability, Availability, and +Serviceability (RAS) Specification"). + +struct kvm_vcpu_events { + struct { + __u8 serror_pending; + __u8 serror_has_esr; + /* Align it to 8 bytes */ + __u8 pad[6]; + __u64 serror_esr; + } exception; + __u32 reserved[12]; +}; + 4.32 KVM_SET_VCPU_EVENTS Capability: KVM_CAP_VCPU_EVENTS Extended by: KVM_CAP_INTR_SHADOW -Architectures: x86 -Type: vm ioctl +Architectures: x86, arm64 +Type: vcpu ioctl Parameters: struct kvm_vcpu_event (in) Returns: 0 on success, -1 on error +X86: + Set pending exceptions, interrupts, and NMIs as well as related states of the vcpu. @@ -910,6 +949,13 @@ shall be written into the VCPU. KVM_VCPUEVENT_VALID_SMM can only be set if KVM_CAP_X86_SMM is available. +ARM64: + +Set the pending SError exception state for this VCPU. It is not possible to +'cancel' an Serror that has been made pending. + +See KVM_GET_VCPU_EVENTS for the data structure. + 4.33 KVM_GET_DEBUGREGS -- cgit v1.2.1 From be26b3a73413c2ebf14d5e76a66ad964e6458080 Mon Sep 17 00:00:00 2001 From: Dongjiu Geng Date: Thu, 19 Jul 2018 16:24:23 +0100 Subject: arm64: KVM: export the capability to set guest SError syndrome For the arm64 RAS Extension, user space can inject a virtual-SError with specified ESR. So user space needs to know whether KVM support to inject such SError, this interface adds this query for this capability. KVM will check whether system support RAS Extension, if supported, KVM returns true to user space, otherwise returns false. Signed-off-by: Dongjiu Geng Reviewed-by: James Morse [expanded documentation wording] Signed-off-by: James Morse Signed-off-by: Marc Zyngier --- Documentation/virtual/kvm/api.txt | 26 ++++++++++++++++++++++++++ 1 file changed, 26 insertions(+) (limited to 'Documentation/virtual') diff --git a/Documentation/virtual/kvm/api.txt b/Documentation/virtual/kvm/api.txt index 284d36e72f28..dbbb95d5798a 100644 --- a/Documentation/virtual/kvm/api.txt +++ b/Documentation/virtual/kvm/api.txt @@ -907,6 +907,18 @@ SError is pending, the architecture's 'Multiple SError interrupts' rules should be followed. (2.5.3 of DDI0587.a "ARM Reliability, Availability, and Serviceability (RAS) Specification"). +SError exceptions always have an ESR value. Some CPUs have the ability to +specify what the virtual SError's ESR value should be. These systems will +advertise KVM_CAP_ARM_SET_SERROR_ESR. In this case exception.has_esr will +always have a non-zero value when read, and the agent making an SError pending +should specify the ISS field in the lower 24 bits of exception.serror_esr. If +the system supports KVM_CAP_ARM_SET_SERROR_ESR, but user-space sets the events +with exception.has_esr as zero, KVM will choose an ESR. + +Specifying exception.has_esr on a system that does not support it will return +-EINVAL. Setting anything other than the lower 24bits of exception.serror_esr +will return -EINVAL. + struct kvm_vcpu_events { struct { __u8 serror_pending; @@ -4664,3 +4676,17 @@ This capability indicates that KVM supports paravirtualized Hyper-V TLB Flush hypercalls: HvFlushVirtualAddressSpace, HvFlushVirtualAddressSpaceEx, HvFlushVirtualAddressList, HvFlushVirtualAddressListEx. + +8.19 KVM_CAP_ARM_SET_SERROR_ESR + +Architectures: arm, arm64 + +This capability indicates that userspace can specify (via the +KVM_SET_VCPU_EVENTS ioctl) the syndrome value reported to the guest when it +takes a virtual SError interrupt exception. +If KVM advertises this capability, userspace can only specify the ISS field for +the ESR syndrome. Other parts of the ESR, such as the EC are generated by the +CPU when the exception is taken. If this virtual SError is taken to EL1 using +AArch64, this value will be reported in the ISS field of ESR_ELx. + +See KVM_CAP_VCPU_EVENTS for more details. -- cgit v1.2.1 From b0960b9569db6b2fe8a75967d47b9dcdeb44016b Mon Sep 17 00:00:00 2001 From: James Morse Date: Thu, 19 Jul 2018 16:24:25 +0100 Subject: KVM: arm: Add 32bit get/set events support arm64's new use of KVMs get_events/set_events API calls isn't just or RAS, it allows an SError that has been made pending by KVM as part of its device emulation to be migrated. Wire this up for 32bit too. We only need to read/write the HCR_VA bit, and check that no esr has been provided, as we don't yet support VDFSR. Signed-off-by: James Morse Reviewed-by: Dongjiu Geng Signed-off-by: Marc Zyngier --- Documentation/virtual/kvm/api.txt | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-) (limited to 'Documentation/virtual') diff --git a/Documentation/virtual/kvm/api.txt b/Documentation/virtual/kvm/api.txt index dbbb95d5798a..4d93fd65bbbd 100644 --- a/Documentation/virtual/kvm/api.txt +++ b/Documentation/virtual/kvm/api.txt @@ -835,7 +835,7 @@ struct kvm_clock_data { Capability: KVM_CAP_VCPU_EVENTS Extended by: KVM_CAP_INTR_SHADOW -Architectures: x86, arm64 +Architectures: x86, arm, arm64 Type: vcpu ioctl Parameters: struct kvm_vcpu_event (out) Returns: 0 on success, -1 on error @@ -883,7 +883,7 @@ Only two fields are defined in the flags field: - KVM_VCPUEVENT_VALID_SMM may be set in the flags field to signal that smi contains a valid state. -ARM64: +ARM/ARM64: If the guest accesses a device that is being emulated by the host kernel in such a way that a real device would generate a physical SError, KVM may make @@ -934,7 +934,7 @@ struct kvm_vcpu_events { Capability: KVM_CAP_VCPU_EVENTS Extended by: KVM_CAP_INTR_SHADOW -Architectures: x86, arm64 +Architectures: x86, arm, arm64 Type: vcpu ioctl Parameters: struct kvm_vcpu_event (in) Returns: 0 on success, -1 on error @@ -961,7 +961,7 @@ shall be written into the VCPU. KVM_VCPUEVENT_VALID_SMM can only be set if KVM_CAP_X86_SMM is available. -ARM64: +ARM/ARM64: Set the pending SError exception state for this VCPU. It is not possible to 'cancel' an Serror that has been made pending. -- cgit v1.2.1