hv.c

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/*
 * Copyright (c) 2009, Microsoft Corporation.
 *
 * This program is free software; you can redistribute it and/or modify it
 * under the terms and conditions of the GNU General Public License,
 * version 2, as published by the Free Software Foundation.
 *
 * This program is distributed in the hope it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
 * more details.
 *
 * You should have received a copy of the GNU General Public License along with
 * this program; if not, write to the Free Software Foundation, Inc., 59 Temple
 * Place - Suite 330, Boston, MA 02111-1307 USA.
 *
 * Authors:
 *   Haiyang Zhang <[email protected]>
 *   Hank Janssen  <[email protected]>
 *
 */
#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

#include <linux/kernel.h>
#include <linux/mm.h>
#include <linux/slab.h>
#include <linux/vmalloc.h>
#include <linux/hyperv.h>
#include <linux/version.h>
#include <asm/hyperv.h>
#include "hyperv_vmbus.h"

/* The one and only */
struct hv_context hv_context = {
    .synic_initialized  = false,
    .hypercall_page     = NULL,
    .signal_event_param = NULL,
    .signal_event_buffer    = NULL,
};

/*
 * query_hypervisor_info - Get version info of the windows hypervisor
 */
static int query_hypervisor_info(void)
{
    unsigned int eax;
    unsigned int ebx;
    unsigned int ecx;
    unsigned int edx;
    unsigned int max_leaf;
    unsigned int op;

    /*
    * Its assumed that this is called after confirming that Viridian
    * is present. Query id and revision.
    */
    eax = 0;
    ebx = 0;
    ecx = 0;
    edx = 0;
    op = HVCPUID_VENDOR_MAXFUNCTION;
    cpuid(op, &eax, &ebx, &ecx, &edx);

    max_leaf = eax;

    if (max_leaf >= HVCPUID_VERSION) {
        eax = 0;
        ebx = 0;
        ecx = 0;
        edx = 0;
        op = HVCPUID_VERSION;
        cpuid(op, &eax, &ebx, &ecx, &edx);
        pr_info("Hyper-V Host OS Build:%d-%d.%d-%d-%d.%d\n",
                eax,
                ebx >> 16,
                ebx & 0xFFFF,
                ecx,
                edx >> 24,
                edx & 0xFFFFFF);
    }
    return max_leaf;
}

/*
 * do_hypercall- Invoke the specified hypercall
 */
static u64 do_hypercall(u64 control, void *input, void *output)
{
#ifdef CONFIG_X86_64
    u64 hv_status = 0;
    u64 input_address = (input) ? virt_to_phys(input) : 0;
    u64 output_address = (output) ? virt_to_phys(output) : 0;
    void *hypercall_page = hv_context.hypercall_page;

    __asm__ __volatile__("mov %0, %%r8" : : "r" (output_address) : "r8");
    __asm__ __volatile__("call *%3" : "=a" (hv_status) :
                 "c" (control), "d" (input_address),
                 "m" (hypercall_page));

    return hv_status;

#else

    u32 control_hi = control >> 32;
    u32 control_lo = control & 0xFFFFFFFF;
    u32 hv_status_hi = 1;
    u32 hv_status_lo = 1;
    u64 input_address = (input) ? virt_to_phys(input) : 0;
    u32 input_address_hi = input_address >> 32;
    u32 input_address_lo = input_address & 0xFFFFFFFF;
    u64 output_address = (output) ? virt_to_phys(output) : 0;
    u32 output_address_hi = output_address >> 32;
    u32 output_address_lo = output_address & 0xFFFFFFFF;
    void *hypercall_page = hv_context.hypercall_page;

    __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_page));

    return hv_status_lo | ((u64)hv_status_hi << 32);
#endif /* !x86_64 */
}

/*
 * hv_init - Main initialization routine.
 *
 * This routine must be called before any other routines in here are called
 */
int hv_init(void)
{
    int max_leaf;
    union hv_x64_msr_hypercall_contents hypercall_msr;
    void *virtaddr = NULL;

    memset(hv_context.synic_event_page, 0, sizeof(void *) * NR_CPUS);
    memset(hv_context.synic_message_page, 0,
           sizeof(void *) * NR_CPUS);

    max_leaf = query_hypervisor_info();

    /*
     * Write our OS ID.
     */
    hv_context.guestid = generate_guest_id(0, LINUX_VERSION_CODE, 0);
    wrmsrl(HV_X64_MSR_GUEST_OS_ID, hv_context.guestid);

    /* See if the hypercall page is already set */
    rdmsrl(HV_X64_MSR_HYPERCALL, hypercall_msr.as_uint64);

    virtaddr = __vmalloc(PAGE_SIZE, GFP_KERNEL, PAGE_KERNEL_EXEC);

    if (!virtaddr)
        goto cleanup;

    hypercall_msr.enable = 1;

    hypercall_msr.guest_physical_address = vmalloc_to_pfn(virtaddr);
    wrmsrl(HV_X64_MSR_HYPERCALL, hypercall_msr.as_uint64);

    /* Confirm that hypercall page did get setup. */
    hypercall_msr.as_uint64 = 0;
    rdmsrl(HV_X64_MSR_HYPERCALL, hypercall_msr.as_uint64);

    if (!hypercall_msr.enable)
        goto cleanup;

    hv_context.hypercall_page = virtaddr;

    /* Setup the global signal event param for the signal event hypercall */
    hv_context.signal_event_buffer =
            kmalloc(sizeof(struct hv_input_signal_event_buffer),
                GFP_KERNEL);
    if (!hv_context.signal_event_buffer)
        goto cleanup;

    hv_context.signal_event_param =
        (struct hv_input_signal_event *)
            (ALIGN((unsigned long)
                  hv_context.signal_event_buffer,
                  HV_HYPERCALL_PARAM_ALIGN));
    hv_context.signal_event_param->connectionid.asu32 = 0;
    hv_context.signal_event_param->connectionid.u.id =
                        VMBUS_EVENT_CONNECTION_ID;
    hv_context.signal_event_param->flag_number = 0;
    hv_context.signal_event_param->rsvdz = 0;

    return 0;

cleanup:
    if (virtaddr) {
        if (hypercall_msr.enable) {
            hypercall_msr.as_uint64 = 0;
            wrmsrl(HV_X64_MSR_HYPERCALL, hypercall_msr.as_uint64);
        }

        vfree(virtaddr);
    }

    return -ENOTSUPP;
}

/*
 * hv_cleanup - Cleanup routine.
 *
 * This routine is called normally during driver unloading or exiting.
 */
void hv_cleanup(void)
{
    union hv_x64_msr_hypercall_contents hypercall_msr;

    /* Reset our OS id */
    wrmsrl(HV_X64_MSR_GUEST_OS_ID, 0);

    kfree(hv_context.signal_event_buffer);
    hv_context.signal_event_buffer = NULL;
    hv_context.signal_event_param = NULL;

    if (hv_context.hypercall_page) {
        hypercall_msr.as_uint64 = 0;
        wrmsrl(HV_X64_MSR_HYPERCALL, hypercall_msr.as_uint64);
        vfree(hv_context.hypercall_page);
        hv_context.hypercall_page = NULL;
    }
}

/*
 * hv_post_message - Post a message using the hypervisor message IPC.
 *
 * This involves a hypercall.
 */
int hv_post_message(union hv_connection_id connection_id,
          enum hv_message_type message_type,
          void *payload, size_t payload_size)
{
    struct aligned_input {
        u64 alignment8;
        struct hv_input_post_message msg;
    };

    struct hv_input_post_message *aligned_msg;
    u16 status;
    unsigned long addr;

    if (payload_size > HV_MESSAGE_PAYLOAD_BYTE_COUNT)
        return -EMSGSIZE;

    addr = (unsigned long)kmalloc(sizeof(struct aligned_input), GFP_ATOMIC);
    if (!addr)
        return -ENOMEM;

    aligned_msg = (struct hv_input_post_message *)
            (ALIGN(addr, HV_HYPERCALL_PARAM_ALIGN));

    aligned_msg->connectionid = connection_id;
    aligned_msg->message_type = message_type;
    aligned_msg->payload_size = payload_size;
    memcpy((void *)aligned_msg->payload, payload, payload_size);

    status = do_hypercall(HVCALL_POST_MESSAGE, aligned_msg, NULL)
        & 0xFFFF;

    kfree((void *)addr);

    return status;
}


/*
 * hv_signal_event -
 * Signal an event on the specified connection using the hypervisor event IPC.
 *
 * This involves a hypercall.
 */
u16 hv_signal_event(void)
{
    u16 status;

    status = do_hypercall(HVCALL_SIGNAL_EVENT,
                   hv_context.signal_event_param,
                   NULL) & 0xFFFF;
    return status;
}

/*
 * hv_synic_init - Initialize the Synthethic Interrupt Controller.
 *
 * If it is already initialized by another entity (ie x2v shim), we need to
 * retrieve the initialized message and event pages.  Otherwise, we create and
 * initialize the message and event pages.
 */
void hv_synic_init(void *irqarg)
{
    u64 version;
    union hv_synic_simp simp;
    union hv_synic_siefp siefp;
    union hv_synic_sint shared_sint;
    union hv_synic_scontrol sctrl;

    u32 irq_vector = *((u32 *)(irqarg));
    int cpu = smp_processor_id();

    if (!hv_context.hypercall_page)
        return;

    /* Check the version */
    rdmsrl(HV_X64_MSR_SVERSION, version);

    hv_context.synic_message_page[cpu] =
        (void *)get_zeroed_page(GFP_ATOMIC);

    if (hv_context.synic_message_page[cpu] == NULL) {
        pr_err("Unable to allocate SYNIC message page\n");
        goto cleanup;
    }

    hv_context.synic_event_page[cpu] =
        (void *)get_zeroed_page(GFP_ATOMIC);

    if (hv_context.synic_event_page[cpu] == NULL) {
        pr_err("Unable to allocate SYNIC event page\n");
        goto cleanup;
    }

    /* Setup the Synic's message page */
    rdmsrl(HV_X64_MSR_SIMP, simp.as_uint64);
    simp.simp_enabled = 1;
    simp.base_simp_gpa = virt_to_phys(hv_context.synic_message_page[cpu])
        >> PAGE_SHIFT;

    wrmsrl(HV_X64_MSR_SIMP, simp.as_uint64);

    /* Setup the Synic's event page */
    rdmsrl(HV_X64_MSR_SIEFP, siefp.as_uint64);
    siefp.siefp_enabled = 1;
    siefp.base_siefp_gpa = virt_to_phys(hv_context.synic_event_page[cpu])
        >> PAGE_SHIFT;

    wrmsrl(HV_X64_MSR_SIEFP, siefp.as_uint64);

    /* Setup the shared SINT. */
    rdmsrl(HV_X64_MSR_SINT0 + VMBUS_MESSAGE_SINT, shared_sint.as_uint64);

    shared_sint.as_uint64 = 0;
    shared_sint.vector = irq_vector; /* HV_SHARED_SINT_IDT_VECTOR + 0x20; */
    shared_sint.masked = false;
    shared_sint.auto_eoi = false;

    wrmsrl(HV_X64_MSR_SINT0 + VMBUS_MESSAGE_SINT, shared_sint.as_uint64);

    /* Enable the global synic bit */
    rdmsrl(HV_X64_MSR_SCONTROL, sctrl.as_uint64);
    sctrl.enable = 1;

    wrmsrl(HV_X64_MSR_SCONTROL, sctrl.as_uint64);

    hv_context.synic_initialized = true;
    return;

cleanup:
    if (hv_context.synic_event_page[cpu])
        free_page((unsigned long)hv_context.synic_event_page[cpu]);

    if (hv_context.synic_message_page[cpu])
        free_page((unsigned long)hv_context.synic_message_page[cpu]);
    return;
}

/*
 * hv_synic_cleanup - Cleanup routine for hv_synic_init().
 */
void hv_synic_cleanup(void *arg)
{
    union hv_synic_sint shared_sint;
    union hv_synic_simp simp;
    union hv_synic_siefp siefp;
    int cpu = smp_processor_id();

    if (!hv_context.synic_initialized)
        return;

    rdmsrl(HV_X64_MSR_SINT0 + VMBUS_MESSAGE_SINT, shared_sint.as_uint64);

    shared_sint.masked = 1;

    /* Need to correctly cleanup in the case of SMP!!! */
    /* Disable the interrupt */
    wrmsrl(HV_X64_MSR_SINT0 + VMBUS_MESSAGE_SINT, shared_sint.as_uint64);

    rdmsrl(HV_X64_MSR_SIMP, simp.as_uint64);
    simp.simp_enabled = 0;
    simp.base_simp_gpa = 0;

    wrmsrl(HV_X64_MSR_SIMP, simp.as_uint64);

    rdmsrl(HV_X64_MSR_SIEFP, siefp.as_uint64);
    siefp.siefp_enabled = 0;
    siefp.base_siefp_gpa = 0;

    wrmsrl(HV_X64_MSR_SIEFP, siefp.as_uint64);

    free_page((unsigned long)hv_context.synic_message_page[cpu]);
    free_page((unsigned long)hv_context.synic_event_page[cpu]);
}