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// SPDX-License-Identifier: MIT License
/*
* hypervisor.c
*
* Communication to/from hypervisor.
*
* Copyright (c) 2002-2003, K A Fraser
* Copyright (c) 2005, Grzegorz Milos, gm281@cam.ac.uk,Intel Research Cambridge
* Copyright (c) 2020, EPAM Systems Inc.
*/
#include <common.h>
#include <cpu_func.h>
#include <log.h>
#include <memalign.h>
#include <asm/io.h>
#include <asm/armv8/mmu.h>
#include <asm/xen/system.h>
#include <linux/bug.h>
#include <xen/hvm.h>
#include <xen/events.h>
#include <xen/gnttab.h>
#include <xen/xenbus.h>
#include <xen/interface/memory.h>
#define active_evtchns(cpu, sh, idx) \
((sh)->evtchn_pending[idx] & \
~(sh)->evtchn_mask[idx])
int in_callback;
/*
* Shared page for communicating with the hypervisor.
* Events flags go here, for example.
*/
struct shared_info *HYPERVISOR_shared_info;
static const char *param_name(int op)
{
#define PARAM(x)[HVM_PARAM_##x] = #x
static const char *const names[] = {
PARAM(CALLBACK_IRQ),
PARAM(STORE_PFN),
PARAM(STORE_EVTCHN),
PARAM(PAE_ENABLED),
PARAM(IOREQ_PFN),
PARAM(VPT_ALIGN),
PARAM(CONSOLE_PFN),
PARAM(CONSOLE_EVTCHN),
};
#undef PARAM
if (op >= ARRAY_SIZE(names))
return "unknown";
if (!names[op])
return "reserved";
return names[op];
}
/**
* hvm_get_parameter_maintain_dcache - function to obtain a HVM
* parameter value.
* @idx: HVM parameter index
* @value: Value to fill in
*
* According to Xen on ARM ABI (xen/include/public/arch-arm.h):
* all memory which is shared with other entities in the system
* (including the hypervisor and other guests) must reside in memory
* which is mapped as Normal Inner Write-Back Outer Write-Back
* Inner-Shareable.
*
* Thus, page attributes must be equally set for all the entities
* working with that page.
*
* Before MMU setup the data cache is turned off, so it means that
* manual data cache maintenance is required, because of the
* difference of page attributes.
*/
int hvm_get_parameter_maintain_dcache(int idx, uint64_t *value)
{
struct xen_hvm_param xhv;
int ret;
invalidate_dcache_range((unsigned long)&xhv,
(unsigned long)&xhv + sizeof(xhv));
xhv.domid = DOMID_SELF;
xhv.index = idx;
invalidate_dcache_range((unsigned long)&xhv,
(unsigned long)&xhv + sizeof(xhv));
ret = HYPERVISOR_hvm_op(HVMOP_get_param, &xhv);
if (ret < 0) {
pr_err("Cannot get hvm parameter %s (%d): %d!\n",
param_name(idx), idx, ret);
BUG();
}
invalidate_dcache_range((unsigned long)&xhv,
(unsigned long)&xhv + sizeof(xhv));
*value = xhv.value;
return ret;
}
int hvm_get_parameter(int idx, uint64_t *value)
{
struct xen_hvm_param xhv;
int ret;
xhv.domid = DOMID_SELF;
xhv.index = idx;
ret = HYPERVISOR_hvm_op(HVMOP_get_param, &xhv);
if (ret < 0) {
pr_err("Cannot get hvm parameter %s (%d): %d!\n",
param_name(idx), idx, ret);
BUG();
}
*value = xhv.value;
return ret;
}
struct shared_info *map_shared_info(void *p)
{
struct xen_add_to_physmap xatp;
HYPERVISOR_shared_info = (struct shared_info *)memalign(PAGE_SIZE,
PAGE_SIZE);
if (!HYPERVISOR_shared_info)
BUG();
xatp.domid = DOMID_SELF;
xatp.idx = 0;
xatp.space = XENMAPSPACE_shared_info;
xatp.gpfn = virt_to_pfn(HYPERVISOR_shared_info);
if (HYPERVISOR_memory_op(XENMEM_add_to_physmap, &xatp) != 0)
BUG();
return HYPERVISOR_shared_info;
}
void do_hypervisor_callback(struct pt_regs *regs)
{
unsigned long l1, l2, l1i, l2i;
unsigned int port;
int cpu = 0;
struct shared_info *s = HYPERVISOR_shared_info;
struct vcpu_info *vcpu_info = &s->vcpu_info[cpu];
in_callback = 1;
vcpu_info->evtchn_upcall_pending = 0;
l1 = xchg(&vcpu_info->evtchn_pending_sel, 0);
while (l1 != 0) {
l1i = __ffs(l1);
l1 &= ~(1UL << l1i);
while ((l2 = active_evtchns(cpu, s, l1i)) != 0) {
l2i = __ffs(l2);
l2 &= ~(1UL << l2i);
port = (l1i * (sizeof(unsigned long) * 8)) + l2i;
do_event(port, regs);
}
}
in_callback = 0;
}
void force_evtchn_callback(void)
{
#ifdef XEN_HAVE_PV_UPCALL_MASK
int save;
#endif
struct vcpu_info *vcpu;
vcpu = &HYPERVISOR_shared_info->vcpu_info[smp_processor_id()];
#ifdef XEN_HAVE_PV_UPCALL_MASK
save = vcpu->evtchn_upcall_mask;
#endif
while (vcpu->evtchn_upcall_pending) {
#ifdef XEN_HAVE_PV_UPCALL_MASK
vcpu->evtchn_upcall_mask = 1;
#endif
do_hypervisor_callback(NULL);
#ifdef XEN_HAVE_PV_UPCALL_MASK
vcpu->evtchn_upcall_mask = save;
#endif
};
}
void mask_evtchn(uint32_t port)
{
struct shared_info *s = HYPERVISOR_shared_info;
synch_set_bit(port, &s->evtchn_mask[0]);
}
void unmask_evtchn(uint32_t port)
{
struct shared_info *s = HYPERVISOR_shared_info;
struct vcpu_info *vcpu_info = &s->vcpu_info[smp_processor_id()];
synch_clear_bit(port, &s->evtchn_mask[0]);
/*
* Just like a real IO-APIC we 'lose the interrupt edge' if the
* channel is masked.
*/
if (synch_test_bit(port, &s->evtchn_pending[0]) &&
!synch_test_and_set_bit(port / (sizeof(unsigned long) * 8),
&vcpu_info->evtchn_pending_sel)) {
vcpu_info->evtchn_upcall_pending = 1;
#ifdef XEN_HAVE_PV_UPCALL_MASK
if (!vcpu_info->evtchn_upcall_mask)
#endif
force_evtchn_callback();
}
}
void clear_evtchn(uint32_t port)
{
struct shared_info *s = HYPERVISOR_shared_info;
synch_clear_bit(port, &s->evtchn_pending[0]);
}
int xen_init(void)
{
debug("%s\n", __func__);
map_shared_info(NULL);
init_events();
init_xenbus();
init_gnttab();
return 0;
}
void xen_fini(void)
{
debug("%s\n", __func__);
fini_gnttab();
fini_xenbus();
fini_events();
}
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