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40da8ccd72
It turns out that we can't handle event channels *entirely* in userspace by delivering them as ExtINT, because KVM is a bit picky about when it accepts ExtINT interrupts from a legacy PIC. The in-kernel local APIC has to have LVT0 configured in APIC_MODE_EXTINT and unmasked, which isn't necessarily the case for Xen guests especially on secondary CPUs. To cope with this, add kvm_xen_get_interrupt() which checks the evtchn_pending_upcall field in the Xen vcpu_info, and delivers the Xen upcall vector (configured by KVM_XEN_ATTR_TYPE_UPCALL_VECTOR) if it's set regardless of LAPIC LVT0 configuration. This gives us the minimum support we need for completely userspace-based implementation of event channels. This does mean that vcpu_enter_guest() needs to check for the evtchn_pending_upcall flag being set, because it can't rely on someone having set KVM_REQ_EVENT unless we were to add some way for userspace to do so manually. Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>
78 lines
2.3 KiB
C
78 lines
2.3 KiB
C
// SPDX-License-Identifier: GPL-2.0
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/*
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* Copyright © 2019 Oracle and/or its affiliates. All rights reserved.
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* Copyright © 2020 Amazon.com, Inc. or its affiliates. All Rights Reserved.
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*
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* KVM Xen emulation
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*/
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#ifndef __ARCH_X86_KVM_XEN_H__
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#define __ARCH_X86_KVM_XEN_H__
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#include <linux/jump_label_ratelimit.h>
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extern struct static_key_false_deferred kvm_xen_enabled;
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int __kvm_xen_has_interrupt(struct kvm_vcpu *vcpu);
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int kvm_xen_vcpu_set_attr(struct kvm_vcpu *vcpu, struct kvm_xen_vcpu_attr *data);
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int kvm_xen_vcpu_get_attr(struct kvm_vcpu *vcpu, struct kvm_xen_vcpu_attr *data);
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int kvm_xen_hvm_set_attr(struct kvm *kvm, struct kvm_xen_hvm_attr *data);
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int kvm_xen_hvm_get_attr(struct kvm *kvm, struct kvm_xen_hvm_attr *data);
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int kvm_xen_hypercall(struct kvm_vcpu *vcpu);
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int kvm_xen_write_hypercall_page(struct kvm_vcpu *vcpu, u64 data);
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int kvm_xen_hvm_config(struct kvm *kvm, struct kvm_xen_hvm_config *xhc);
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void kvm_xen_destroy_vm(struct kvm *kvm);
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static inline bool kvm_xen_hypercall_enabled(struct kvm *kvm)
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{
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return static_branch_unlikely(&kvm_xen_enabled.key) &&
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(kvm->arch.xen_hvm_config.flags &
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KVM_XEN_HVM_CONFIG_INTERCEPT_HCALL);
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}
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static inline int kvm_xen_has_interrupt(struct kvm_vcpu *vcpu)
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{
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if (static_branch_unlikely(&kvm_xen_enabled.key) &&
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vcpu->arch.xen.vcpu_info_set && vcpu->kvm->arch.xen.upcall_vector)
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return __kvm_xen_has_interrupt(vcpu);
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return 0;
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}
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/* 32-bit compatibility definitions, also used natively in 32-bit build */
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#include <asm/pvclock-abi.h>
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#include <asm/xen/interface.h>
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struct compat_arch_vcpu_info {
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unsigned int cr2;
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unsigned int pad[5];
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};
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struct compat_vcpu_info {
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uint8_t evtchn_upcall_pending;
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uint8_t evtchn_upcall_mask;
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uint32_t evtchn_pending_sel;
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struct compat_arch_vcpu_info arch;
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struct pvclock_vcpu_time_info time;
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}; /* 64 bytes (x86) */
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struct compat_arch_shared_info {
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unsigned int max_pfn;
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unsigned int pfn_to_mfn_frame_list_list;
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unsigned int nmi_reason;
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unsigned int p2m_cr3;
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unsigned int p2m_vaddr;
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unsigned int p2m_generation;
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uint32_t wc_sec_hi;
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};
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struct compat_shared_info {
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struct compat_vcpu_info vcpu_info[MAX_VIRT_CPUS];
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uint32_t evtchn_pending[32];
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uint32_t evtchn_mask[32];
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struct pvclock_wall_clock wc;
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struct compat_arch_shared_info arch;
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};
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#endif /* __ARCH_X86_KVM_XEN_H__ */
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