forked from Minki/linux
a43fb7da53
We need to refactor PVH entry code so that support for other hypervisors like Qemu/KVM can be added more easily. The original design for PVH entry in Xen guests relies on being able to obtain the memory map from the hypervisor using a hypercall. When we extend the PVH entry ABI to support other hypervisors like Qemu/KVM, a new mechanism will be added that allows the guest to get the memory map without needing to use hypercalls. For Xen guests, the hypercall approach will still be supported. In preparation for adding support for other hypervisors, we can move the code that uses hypercalls into the Xen specific file. This will allow us to compile kernels in the future without CONFIG_XEN that are still capable of being booted as a Qemu/KVM guest via the PVH entry point. Signed-off-by: Maran Wilson <maran.wilson@oracle.com> Reviewed-by: Juergen Gross <jgross@suse.com> Signed-off-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
118 lines
3.2 KiB
C
118 lines
3.2 KiB
C
// SPDX-License-Identifier: GPL-2.0
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#include <linux/acpi.h>
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#include <xen/hvc-console.h>
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#include <asm/io_apic.h>
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#include <asm/hypervisor.h>
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#include <asm/e820/api.h>
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#include <asm/x86_init.h>
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#include <xen/xen.h>
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#include <xen/interface/hvm/start_info.h>
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/*
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* PVH variables.
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*
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* pvh_bootparams and pvh_start_info need to live in the data segment since
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* they are used after startup_{32|64}, which clear .bss, are invoked.
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*/
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struct boot_params pvh_bootparams __attribute__((section(".data")));
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struct hvm_start_info pvh_start_info __attribute__((section(".data")));
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unsigned int pvh_start_info_sz = sizeof(pvh_start_info);
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static u64 pvh_get_root_pointer(void)
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{
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return pvh_start_info.rsdp_paddr;
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}
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/*
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* Xen guests are able to obtain the memory map from the hypervisor via the
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* HYPERVISOR_memory_op hypercall.
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* If we are trying to boot a Xen PVH guest, it is expected that the kernel
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* will have been configured to provide an override for this routine to do
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* just that.
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*/
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void __init __weak mem_map_via_hcall(struct boot_params *ptr __maybe_unused)
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{
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xen_raw_printk("Error: Could not find memory map\n");
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BUG();
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}
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static void __init init_pvh_bootparams(void)
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{
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memset(&pvh_bootparams, 0, sizeof(pvh_bootparams));
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mem_map_via_hcall(&pvh_bootparams);
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if (pvh_bootparams.e820_entries < E820_MAX_ENTRIES_ZEROPAGE - 1) {
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pvh_bootparams.e820_table[pvh_bootparams.e820_entries].addr =
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ISA_START_ADDRESS;
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pvh_bootparams.e820_table[pvh_bootparams.e820_entries].size =
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ISA_END_ADDRESS - ISA_START_ADDRESS;
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pvh_bootparams.e820_table[pvh_bootparams.e820_entries].type =
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E820_TYPE_RESERVED;
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pvh_bootparams.e820_entries++;
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} else
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xen_raw_printk("Warning: Can fit ISA range into e820\n");
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pvh_bootparams.hdr.cmd_line_ptr =
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pvh_start_info.cmdline_paddr;
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/* The first module is always ramdisk. */
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if (pvh_start_info.nr_modules) {
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struct hvm_modlist_entry *modaddr =
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__va(pvh_start_info.modlist_paddr);
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pvh_bootparams.hdr.ramdisk_image = modaddr->paddr;
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pvh_bootparams.hdr.ramdisk_size = modaddr->size;
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}
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/*
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* See Documentation/x86/boot.txt.
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*
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* Version 2.12 supports Xen entry point but we will use default x86/PC
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* environment (i.e. hardware_subarch 0).
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*/
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pvh_bootparams.hdr.version = (2 << 8) | 12;
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pvh_bootparams.hdr.type_of_loader = (9 << 4) | 0; /* Xen loader */
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x86_init.acpi.get_root_pointer = pvh_get_root_pointer;
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}
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/*
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* If we are trying to boot a Xen PVH guest, it is expected that the kernel
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* will have been configured to provide the required override for this routine.
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*/
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void __init __weak xen_pvh_init(void)
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{
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xen_raw_printk("Error: Missing xen PVH initialization\n");
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BUG();
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}
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/*
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* When we add support for other hypervisors like Qemu/KVM, this routine can
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* selectively invoke the appropriate initialization based on guest type.
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*/
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static void hypervisor_specific_init(void)
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{
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xen_pvh_init();
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}
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/*
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* This routine (and those that it might call) should not use
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* anything that lives in .bss since that segment will be cleared later.
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*/
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void __init xen_prepare_pvh(void)
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{
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if (pvh_start_info.magic != XEN_HVM_START_MAGIC_VALUE) {
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xen_raw_printk("Error: Unexpected magic value (0x%08x)\n",
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pvh_start_info.magic);
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BUG();
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}
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hypervisor_specific_init();
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init_pvh_bootparams();
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}
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