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/*
* X86 specific Hyper-V initialization code.
*
* Copyright (C) 2016, Microsoft, Inc.
*
* Author : K. Y. Srinivasan <kys@microsoft.com>
*
* This program is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License version 2 as published
* by the Free Software Foundation.
*
* This program is distributed in the hope that it will be useful, but
* WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE, GOOD TITLE or
* NON INFRINGEMENT. See the GNU General Public License for more
* details.
*
*/
#include <linux/types.h>
#include <asm/hypervisor.h>
#include <asm/hyperv.h>
#include <asm/mshyperv.h>
#include <linux/version.h>
#include <linux/vmalloc.h>
#include <linux/mm.h>
static void *hypercall_pg;
/*
* This function is to be invoked early in the boot sequence after the
* hypervisor has been detected.
*
* 1. Setup the hypercall page.
*/
void hyperv_init(void)
{
u64 guest_id;
union hv_x64_msr_hypercall_contents hypercall_msr;
if (x86_hyper != &x86_hyper_ms_hyperv)
return;
/*
* Setup the hypercall page and enable hypercalls.
* 1. Register the guest ID
* 2. Enable the hypercall and register the hypercall page
*/
guest_id = generate_guest_id(0, LINUX_VERSION_CODE, 0);
wrmsrl(HV_X64_MSR_GUEST_OS_ID, guest_id);
hypercall_pg = __vmalloc(PAGE_SIZE, GFP_KERNEL, PAGE_KERNEL_EXEC);
if (hypercall_pg == NULL) {
wrmsrl(HV_X64_MSR_GUEST_OS_ID, 0);
return;
}
rdmsrl(HV_X64_MSR_HYPERCALL, hypercall_msr.as_uint64);
hypercall_msr.enable = 1;
hypercall_msr.guest_physical_address = vmalloc_to_pfn(hypercall_pg);
wrmsrl(HV_X64_MSR_HYPERCALL, hypercall_msr.as_uint64);
}
/*
* hv_do_hypercall- Invoke the specified hypercall
*/
u64 hv_do_hypercall(u64 control, void *input, void *output)
{
u64 input_address = (input) ? virt_to_phys(input) : 0;
u64 output_address = (output) ? virt_to_phys(output) : 0;
#ifdef CONFIG_X86_64
u64 hv_status = 0;
if (!hypercall_pg)
return (u64)ULLONG_MAX;
__asm__ __volatile__("mov %0, %%r8" : : "r" (output_address) : "r8");
__asm__ __volatile__("call *%3" : "=a" (hv_status) :
"c" (control), "d" (input_address),
"m" (hypercall_pg));
return hv_status;
#else
u32 control_hi = control >> 32;
u32 control_lo = control & 0xFFFFFFFF;
u32 hv_status_hi = 1;
u32 hv_status_lo = 1;
u32 input_address_hi = input_address >> 32;
u32 input_address_lo = input_address & 0xFFFFFFFF;
u32 output_address_hi = output_address >> 32;
u32 output_address_lo = output_address & 0xFFFFFFFF;
if (!hypercall_pg)
return (u64)ULLONG_MAX;
__asm__ __volatile__ ("call *%8" : "=d"(hv_status_hi),
"=a"(hv_status_lo) : "d" (control_hi),
"a" (control_lo), "b" (input_address_hi),
"c" (input_address_lo), "D"(output_address_hi),
"S"(output_address_lo), "m" (hypercall_pg));
return hv_status_lo | ((u64)hv_status_hi << 32);
#endif /* !x86_64 */
}
EXPORT_SYMBOL_GPL(hv_do_hypercall);
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