Commit be26b3a7 authored by Dongjiu Geng's avatar Dongjiu Geng Committed by Marc Zyngier
Browse files

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: default avatarDongjiu Geng <gengdongjiu@huawei.com>
Reviewed-by: default avatarJames Morse <james.morse@arm.com>
[expanded documentation wording]
Signed-off-by: default avatarJames Morse <james.morse@arm.com>
Signed-off-by: default avatarMarc Zyngier <marc.zyngier@arm.com>
parent b7b27fac

Documentation/virtual/kvm/api.txt

+26 −0
Original line number Diff line number Diff line
@@ -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.

arch/arm64/kvm/reset.c

+3 −0
Original line number Diff line number Diff line
@@ -77,6 +77,9 @@ int kvm_arch_dev_ioctl_check_extension(struct kvm *kvm, long ext) 
	case KVM_CAP_ARM_PMU_V3:

		r = kvm_arm_support_pmu_v3();

		break;

	case KVM_CAP_ARM_INJECT_SERROR_ESR:

		r = cpus_have_const_cap(ARM64_HAS_RAS_EXTN);

		break;

	case KVM_CAP_SET_GUEST_DEBUG:

	case KVM_CAP_VCPU_ATTRIBUTES:

	case KVM_CAP_VCPU_EVENTS:

include/uapi/linux/kvm.h

+1 −0
Original line number Diff line number Diff line
@@ -949,6 +949,7 @@ struct kvm_ppc_resize_hpt { 
#define KVM_CAP_GET_MSR_FEATURES 153

#define KVM_CAP_HYPERV_EVENTFD 154

#define KVM_CAP_HYPERV_TLBFLUSH 155

#define KVM_CAP_ARM_INJECT_SERROR_ESR 156



#ifdef KVM_CAP_IRQ_ROUTING

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