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/*
* Xen HVM emulation support in KVM
*
* Copyright © 2019 Oracle and/or its affiliates. All rights reserved.
* Copyright © 2022 Amazon.com, Inc. or its affiliates. All Rights Reserved.
*
* This work is licensed under the terms of the GNU GPL, version 2 or later.
* See the COPYING file in the top-level directory.
*
*/
#include "qemu/osdep.h"
#include "qemu/log.h"
#include "sysemu/kvm_int.h"
#include "sysemu/kvm_xen.h"
#include "kvm/kvm_i386.h"
#include "exec/address-spaces.h"
#include "xen-emu.h"
#include "trace.h"
#include "hw/xen/interface/version.h"
static int kvm_gva_rw(CPUState *cs, uint64_t gva, void *_buf, size_t sz,
bool is_write)
{
uint8_t *buf = (uint8_t *)_buf;
int ret;
while (sz) {
struct kvm_translation tr = {
.linear_address = gva,
};
size_t len = TARGET_PAGE_SIZE - (tr.linear_address & ~TARGET_PAGE_MASK);
if (len > sz) {
len = sz;
}
ret = kvm_vcpu_ioctl(cs, KVM_TRANSLATE, &tr);
if (ret || !tr.valid || (is_write && !tr.writeable)) {
return -EFAULT;
}
cpu_physical_memory_rw(tr.physical_address, buf, len, is_write);
buf += len;
sz -= len;
gva += len;
}
return 0;
}
static inline int kvm_copy_from_gva(CPUState *cs, uint64_t gva, void *buf,
size_t sz)
{
return kvm_gva_rw(cs, gva, buf, sz, false);
}
static inline int kvm_copy_to_gva(CPUState *cs, uint64_t gva, void *buf,
size_t sz)
{
return kvm_gva_rw(cs, gva, buf, sz, true);
}
int kvm_xen_init(KVMState *s, uint32_t hypercall_msr)
{
const int required_caps = KVM_XEN_HVM_CONFIG_HYPERCALL_MSR |
KVM_XEN_HVM_CONFIG_INTERCEPT_HCALL | KVM_XEN_HVM_CONFIG_SHARED_INFO;
struct kvm_xen_hvm_config cfg = {
.msr = hypercall_msr,
.flags = KVM_XEN_HVM_CONFIG_INTERCEPT_HCALL,
};
int xen_caps, ret;
xen_caps = kvm_check_extension(s, KVM_CAP_XEN_HVM);
if (required_caps & ~xen_caps) {
error_report("kvm: Xen HVM guest support not present or insufficient");
return -ENOSYS;
}
if (xen_caps & KVM_XEN_HVM_CONFIG_EVTCHN_SEND) {
struct kvm_xen_hvm_attr ha = {
.type = KVM_XEN_ATTR_TYPE_XEN_VERSION,
.u.xen_version = s->xen_version,
};
(void)kvm_vm_ioctl(s, KVM_XEN_HVM_SET_ATTR, &ha);
cfg.flags |= KVM_XEN_HVM_CONFIG_EVTCHN_SEND;
}
ret = kvm_vm_ioctl(s, KVM_XEN_HVM_CONFIG, &cfg);
if (ret < 0) {
error_report("kvm: Failed to enable Xen HVM support: %s",
strerror(-ret));
return ret;
}
s->xen_caps = xen_caps;
return 0;
}
int kvm_xen_init_vcpu(CPUState *cs)
{
int err;
/*
* The kernel needs to know the Xen/ACPI vCPU ID because that's
* what the guest uses in hypercalls such as timers. It doesn't
* match the APIC ID which is generally used for talking to the
* kernel about vCPUs. And if vCPU threads race with creating
* their KVM vCPUs out of order, it doesn't necessarily match
* with the kernel's internal vCPU indices either.
*/
if (kvm_xen_has_cap(EVTCHN_SEND)) {
struct kvm_xen_vcpu_attr va = {
.type = KVM_XEN_VCPU_ATTR_TYPE_VCPU_ID,
.u.vcpu_id = cs->cpu_index,
};
err = kvm_vcpu_ioctl(cs, KVM_XEN_VCPU_SET_ATTR, &va);
if (err) {
error_report("kvm: Failed to set Xen vCPU ID attribute: %s",
strerror(-err));
return err;
}
}
return 0;
}
uint32_t kvm_xen_get_caps(void)
{
return kvm_state->xen_caps;
}
static bool kvm_xen_hcall_xen_version(struct kvm_xen_exit *exit, X86CPU *cpu,
int cmd, uint64_t arg)
{
int err = 0;
switch (cmd) {
case XENVER_get_features: {
struct xen_feature_info fi;
/* No need for 32/64 compat handling */
qemu_build_assert(sizeof(fi) == 8);
err = kvm_copy_from_gva(CPU(cpu), arg, &fi, sizeof(fi));
if (err) {
break;
}
fi.submap = 0;
if (fi.submap_idx == 0) {
fi.submap |= 1 << XENFEAT_writable_page_tables |
1 << XENFEAT_writable_descriptor_tables |
1 << XENFEAT_auto_translated_physmap |
1 << XENFEAT_supervisor_mode_kernel;
}
err = kvm_copy_to_gva(CPU(cpu), arg, &fi, sizeof(fi));
break;
}
default:
return false;
}
exit->u.hcall.result = err;
return true;
}
static bool do_kvm_xen_handle_exit(X86CPU *cpu, struct kvm_xen_exit *exit)
{
uint16_t code = exit->u.hcall.input;
if (exit->u.hcall.cpl > 0) {
exit->u.hcall.result = -EPERM;
return true;
}
switch (code) {
case __HYPERVISOR_xen_version:
return kvm_xen_hcall_xen_version(exit, cpu, exit->u.hcall.params[0],
exit->u.hcall.params[1]);
default:
return false;
}
}
int kvm_xen_handle_exit(X86CPU *cpu, struct kvm_xen_exit *exit)
{
if (exit->type != KVM_EXIT_XEN_HCALL) {
return -1;
}
if (!do_kvm_xen_handle_exit(cpu, exit)) {
/*
* Some hypercalls will be deliberately "implemented" by returning
* -ENOSYS. This case is for hypercalls which are unexpected.
*/
exit->u.hcall.result = -ENOSYS;
qemu_log_mask(LOG_UNIMP, "Unimplemented Xen hypercall %"
PRId64 " (0x%" PRIx64 " 0x%" PRIx64 " 0x%" PRIx64 ")\n",
(uint64_t)exit->u.hcall.input,
(uint64_t)exit->u.hcall.params[0],
(uint64_t)exit->u.hcall.params[1],
(uint64_t)exit->u.hcall.params[2]);
}
trace_kvm_xen_hypercall(CPU(cpu)->cpu_index, exit->u.hcall.cpl,
exit->u.hcall.input, exit->u.hcall.params[0],
exit->u.hcall.params[1], exit->u.hcall.params[2],
exit->u.hcall.result);
return 0;
}
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