mirror of
https://github.com/AsahiLinux/u-boot
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0001a964b8
This commit fixes issue with usage of Xen hypervisor shared info page. Previously U-boot did not unmap it at the end of OS boot process. Xen did not prevent guest from this. So, it worked, but caused wierd issues - one memory page, that was returned by memalign in U-boot for Enlighten mapping was not unmaped by Xen (shared_info values was not removed from there) and returned to allocator. During the Linux boot, it uses shared_info page as regular RAM page, which leads to hypervisor shared info corruption. So, to fix this issue, as discussed on the xen-devel mailing list, the code should: 1) Unmap the page 2) Populate the area with memory using XENMEM_populate_physmap This patch adds page unmapping via XENMEM_remove_from_physmap, fills hole in address space where page was mapped via XENMEM_populate_physmap and return this address to memory allocator for freeing. Signed-off-by: Dmytro Firsov <dmytro_firsov@epam.com> Reviewed-by: Anastasiia Lukianenko <vicooodin@gmail.com>
285 lines
6.5 KiB
C
285 lines
6.5 KiB
C
// SPDX-License-Identifier: MIT License
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/*
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* hypervisor.c
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*
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* Communication to/from hypervisor.
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*
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* Copyright (c) 2002-2003, K A Fraser
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* Copyright (c) 2005, Grzegorz Milos, gm281@cam.ac.uk,Intel Research Cambridge
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* Copyright (c) 2020, EPAM Systems Inc.
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*/
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#include <common.h>
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#include <cpu_func.h>
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#include <log.h>
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#include <memalign.h>
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#include <asm/io.h>
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#include <asm/armv8/mmu.h>
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#include <asm/xen/system.h>
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#include <linux/bug.h>
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#include <xen/hvm.h>
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#include <xen/events.h>
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#include <xen/gnttab.h>
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#include <xen/xenbus.h>
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#include <xen/interface/memory.h>
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#define active_evtchns(cpu, sh, idx) \
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((sh)->evtchn_pending[idx] & \
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~(sh)->evtchn_mask[idx])
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int in_callback;
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/*
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* Shared page for communicating with the hypervisor.
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* Events flags go here, for example.
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*/
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struct shared_info *HYPERVISOR_shared_info;
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static const char *param_name(int op)
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{
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#define PARAM(x)[HVM_PARAM_##x] = #x
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static const char *const names[] = {
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PARAM(CALLBACK_IRQ),
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PARAM(STORE_PFN),
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PARAM(STORE_EVTCHN),
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PARAM(PAE_ENABLED),
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PARAM(IOREQ_PFN),
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PARAM(VPT_ALIGN),
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PARAM(CONSOLE_PFN),
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PARAM(CONSOLE_EVTCHN),
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};
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#undef PARAM
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if (op >= ARRAY_SIZE(names))
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return "unknown";
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if (!names[op])
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return "reserved";
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return names[op];
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}
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/**
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* hvm_get_parameter_maintain_dcache - function to obtain a HVM
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* parameter value.
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* @idx: HVM parameter index
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* @value: Value to fill in
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*
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* According to Xen on ARM ABI (xen/include/public/arch-arm.h):
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* all memory which is shared with other entities in the system
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* (including the hypervisor and other guests) must reside in memory
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* which is mapped as Normal Inner Write-Back Outer Write-Back
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* Inner-Shareable.
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*
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* Thus, page attributes must be equally set for all the entities
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* working with that page.
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*
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* Before MMU setup the data cache is turned off, so it means that
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* manual data cache maintenance is required, because of the
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* difference of page attributes.
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*/
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int hvm_get_parameter_maintain_dcache(int idx, uint64_t *value)
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{
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struct xen_hvm_param xhv;
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int ret;
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invalidate_dcache_range((unsigned long)&xhv,
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(unsigned long)&xhv + sizeof(xhv));
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xhv.domid = DOMID_SELF;
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xhv.index = idx;
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invalidate_dcache_range((unsigned long)&xhv,
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(unsigned long)&xhv + sizeof(xhv));
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ret = HYPERVISOR_hvm_op(HVMOP_get_param, &xhv);
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if (ret < 0) {
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pr_err("Cannot get hvm parameter %s (%d): %d!\n",
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param_name(idx), idx, ret);
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BUG();
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}
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invalidate_dcache_range((unsigned long)&xhv,
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(unsigned long)&xhv + sizeof(xhv));
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*value = xhv.value;
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return ret;
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}
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int hvm_get_parameter(int idx, uint64_t *value)
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{
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struct xen_hvm_param xhv;
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int ret;
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xhv.domid = DOMID_SELF;
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xhv.index = idx;
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ret = HYPERVISOR_hvm_op(HVMOP_get_param, &xhv);
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if (ret < 0) {
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pr_err("Cannot get hvm parameter %s (%d): %d!\n",
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param_name(idx), idx, ret);
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BUG();
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}
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*value = xhv.value;
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return ret;
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}
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struct shared_info *map_shared_info(void *p)
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{
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struct xen_add_to_physmap xatp;
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HYPERVISOR_shared_info = (struct shared_info *)memalign(PAGE_SIZE,
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PAGE_SIZE);
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if (!HYPERVISOR_shared_info)
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BUG();
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xatp.domid = DOMID_SELF;
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xatp.idx = 0;
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xatp.space = XENMAPSPACE_shared_info;
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xatp.gpfn = virt_to_pfn(HYPERVISOR_shared_info);
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if (HYPERVISOR_memory_op(XENMEM_add_to_physmap, &xatp) != 0)
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BUG();
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return HYPERVISOR_shared_info;
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}
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void unmap_shared_info(void)
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{
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xen_pfn_t shared_info_pfn = virt_to_pfn(HYPERVISOR_shared_info);
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struct xen_remove_from_physmap xrfp = {0};
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struct xen_memory_reservation reservation = {0};
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xen_ulong_t nr_exts = 1;
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xrfp.domid = DOMID_SELF;
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xrfp.gpfn = shared_info_pfn;
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if (HYPERVISOR_memory_op(XENMEM_remove_from_physmap, &xrfp) != 0)
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panic("Failed to unmap HYPERVISOR_shared_info\n");
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/*
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* After removing from physmap there will be a hole in address space on
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* HYPERVISOR_shared_info address, so to free memory allocated with
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* memalign and prevent exceptions during access to this page we need to
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* fill this 4KB hole with XENMEM_populate_physmap before jumping to Linux.
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*/
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reservation.domid = DOMID_SELF;
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reservation.extent_order = 0;
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reservation.address_bits = 0;
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set_xen_guest_handle(reservation.extent_start, &shared_info_pfn);
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reservation.nr_extents = nr_exts;
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if (HYPERVISOR_memory_op(XENMEM_populate_physmap, &reservation) != nr_exts)
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panic("Failed to populate memory on HYPERVISOR_shared_info addr\n");
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/* Now we can return this to memory allocator */
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free(HYPERVISOR_shared_info);
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}
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void do_hypervisor_callback(struct pt_regs *regs)
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{
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unsigned long l1, l2, l1i, l2i;
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unsigned int port;
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int cpu = 0;
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struct shared_info *s = HYPERVISOR_shared_info;
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struct vcpu_info *vcpu_info = &s->vcpu_info[cpu];
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in_callback = 1;
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vcpu_info->evtchn_upcall_pending = 0;
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l1 = xchg(&vcpu_info->evtchn_pending_sel, 0);
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while (l1 != 0) {
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l1i = __ffs(l1);
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l1 &= ~(1UL << l1i);
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while ((l2 = active_evtchns(cpu, s, l1i)) != 0) {
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l2i = __ffs(l2);
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l2 &= ~(1UL << l2i);
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port = (l1i * (sizeof(unsigned long) * 8)) + l2i;
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do_event(port, regs);
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}
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}
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in_callback = 0;
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}
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void force_evtchn_callback(void)
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{
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#ifdef XEN_HAVE_PV_UPCALL_MASK
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int save;
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#endif
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struct vcpu_info *vcpu;
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vcpu = &HYPERVISOR_shared_info->vcpu_info[smp_processor_id()];
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#ifdef XEN_HAVE_PV_UPCALL_MASK
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save = vcpu->evtchn_upcall_mask;
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#endif
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while (vcpu->evtchn_upcall_pending) {
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#ifdef XEN_HAVE_PV_UPCALL_MASK
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vcpu->evtchn_upcall_mask = 1;
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#endif
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do_hypervisor_callback(NULL);
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#ifdef XEN_HAVE_PV_UPCALL_MASK
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vcpu->evtchn_upcall_mask = save;
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#endif
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};
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}
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void mask_evtchn(uint32_t port)
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{
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struct shared_info *s = HYPERVISOR_shared_info;
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synch_set_bit(port, &s->evtchn_mask[0]);
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}
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void unmask_evtchn(uint32_t port)
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{
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struct shared_info *s = HYPERVISOR_shared_info;
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struct vcpu_info *vcpu_info = &s->vcpu_info[smp_processor_id()];
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synch_clear_bit(port, &s->evtchn_mask[0]);
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/*
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* Just like a real IO-APIC we 'lose the interrupt edge' if the
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* channel is masked.
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*/
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if (synch_test_bit(port, &s->evtchn_pending[0]) &&
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!synch_test_and_set_bit(port / (sizeof(unsigned long) * 8),
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&vcpu_info->evtchn_pending_sel)) {
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vcpu_info->evtchn_upcall_pending = 1;
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#ifdef XEN_HAVE_PV_UPCALL_MASK
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if (!vcpu_info->evtchn_upcall_mask)
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#endif
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force_evtchn_callback();
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}
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}
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void clear_evtchn(uint32_t port)
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{
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struct shared_info *s = HYPERVISOR_shared_info;
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synch_clear_bit(port, &s->evtchn_pending[0]);
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}
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int xen_init(void)
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{
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debug("%s\n", __func__);
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map_shared_info(NULL);
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init_events();
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init_xenbus();
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init_gnttab();
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return 0;
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}
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void xen_fini(void)
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{
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debug("%s\n", __func__);
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fini_gnttab();
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fini_xenbus();
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fini_events();
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unmap_shared_info();
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}
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