diff options
Diffstat (limited to 'drivers/xen')
| -rw-r--r-- | drivers/xen/Makefile | 5 | ||||
| -rw-r--r-- | drivers/xen/hypervisor.c | 240 |
2 files changed, 245 insertions, 0 deletions
diff --git a/drivers/xen/Makefile b/drivers/xen/Makefile new file mode 100644 index 0000000..1211bf2 --- /dev/null +++ b/drivers/xen/Makefile @@ -0,0 +1,5 @@ +# SPDX-License-Identifier: GPL-2.0+ +# +# (C) Copyright 2020 EPAM Systems Inc. + +obj-y += hypervisor.o diff --git a/drivers/xen/hypervisor.c b/drivers/xen/hypervisor.c new file mode 100644 index 0000000..108e970 --- /dev/null +++ b/drivers/xen/hypervisor.c @@ -0,0 +1,240 @@ +// 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/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; + /* TODO: handle new event: do_event(port, regs); */ + /* Suppress -Wunused-but-set-variable */ + (void)(port); + } + } + + 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]); +} + +void xen_init(void) +{ + debug("%s\n", __func__); + + map_shared_info(NULL); +} + |