hvm.c

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/*
 * hvm.c: Common hardware virtual machine abstractions.
 *
 * Copyright (c) 2004, Intel Corporation.
 * Copyright (c) 2005, International Business Machines Corporation.
 * Copyright (c) 2008, Citrix Systems, Inc.
 * 
 * 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.
 */

#include <xen/config.h>
#include <xen/init.h>
#include <xen/lib.h>
#include <xen/trace.h>
#include <xen/sched.h>
#include <xen/irq.h>
#include <xen/softirq.h>
#include <xen/domain.h>
#include <xen/domain_page.h>
#include <xen/hypercall.h>
#include <xen/guest_access.h>
#include <xen/event.h>
#include <asm/current.h>
#include <asm/e820.h>
#include <asm/io.h>
#include <asm/paging.h>
#include <asm/regs.h>
#include <asm/cpufeature.h>
#include <asm/processor.h>
#include <asm/types.h>
#include <asm/msr.h>
#include <asm/mc146818rtc.h>
#include <asm/spinlock.h>
#include <asm/hvm/hvm.h>
#include <asm/hvm/vpt.h>
#include <asm/hvm/support.h>
#include <asm/hvm/cacheattr.h>
#include <asm/hvm/trace.h>
#include <public/sched.h>
#include <public/hvm/ioreq.h>
#include <public/version.h>
#include <public/memory.h>

int hvm_enabled __read_mostly;

unsigned int opt_hvm_debug_level __read_mostly;
integer_param("hvm_debug", opt_hvm_debug_level);

int opt_softtsc;
boolean_param("softtsc", opt_softtsc);

struct hvm_function_table hvm_funcs __read_mostly;

/* I/O permission bitmap is globally shared by all HVM guests. */
unsigned long __attribute__ ((__section__ (".bss.page_aligned")))
    hvm_io_bitmap[3*PAGE_SIZE/BYTES_PER_LONG];

void hvm_enable(struct hvm_function_table *fns)
{
    BUG_ON(hvm_enabled);
    printk("HVM: %s enabled\n", fns->name);

    /*
     * Allow direct access to the PC debug port (it is often used for I/O
     * delays, but the vmexits simply slow things down).
     */
    memset(hvm_io_bitmap, ~0, sizeof(hvm_io_bitmap));
    __clear_bit(0x80, hvm_io_bitmap);

    hvm_funcs   = *fns;
    hvm_enabled = 1;

    if ( hvm_funcs.hap_supported )
        printk("HVM: Hardware Assisted Paging detected.\n");
}

/*
 * Need to re-inject a given event? We avoid re-injecting software exceptions
 * and interrupts because the faulting/trapping instruction can simply be
 * re-executed (neither VMX nor SVM update RIP when they VMEXIT during
 * INT3/INTO/INTn).
 */
int hvm_event_needs_reinjection(uint8_t type, uint8_t vector)
{
    switch ( type )
    {
    case X86_EVENTTYPE_EXT_INTR:
    case X86_EVENTTYPE_NMI:
        return 1;
    case X86_EVENTTYPE_HW_EXCEPTION:
        /*
         * SVM uses type 3 ("HW Exception") for #OF and #BP. We explicitly
         * check for these vectors, as they are really SW Exceptions. SVM has
         * not updated RIP to point after the trapping instruction (INT3/INTO).
         */
        return (vector != 3) && (vector != 4);
    default:
        /* Software exceptions/interrupts can be re-executed (e.g., INT n). */
        break;
    }
    return 0;
}

/*
 * Combine two hardware exceptions: @vec2 was raised during delivery of @vec1.
 * This means we can assume that @vec2 is contributory or a page fault.
 */
uint8_t hvm_combine_hw_exceptions(uint8_t vec1, uint8_t vec2)
{
    /* Exception during double-fault delivery always causes a triple fault. */
    if ( vec1 == TRAP_double_fault )
    {
        hvm_triple_fault();
        return TRAP_double_fault; /* dummy return */
    }

    /* Exception during page-fault delivery always causes a double fault. */
    if ( vec1 == TRAP_page_fault )
        return TRAP_double_fault;

    /* Discard the first exception if it's benign or if we now have a #PF. */
    if ( !((1u << vec1) & 0x7c01u) || (vec2 == TRAP_page_fault) )
        return vec2;

    /* Cannot combine the exceptions: double fault. */
    return TRAP_double_fault;
}

void hvm_set_guest_tsc(struct vcpu *v, u64 guest_tsc)
{
    u64 host_tsc;

    rdtscll(host_tsc);

    v->arch.hvm_vcpu.cache_tsc_offset = guest_tsc - host_tsc;
    hvm_funcs.set_tsc_offset(v, v->arch.hvm_vcpu.cache_tsc_offset);
}

u64 hvm_get_guest_tsc(struct vcpu *v)
{
    u64 host_tsc;

    if ( opt_softtsc )
        host_tsc = hvm_get_guest_time(v);
    else
        rdtscll(host_tsc);

    return host_tsc + v->arch.hvm_vcpu.cache_tsc_offset;
}

void hvm_migrate_timers(struct vcpu *v)
{
    rtc_migrate_timers(v);
    hpet_migrate_timers(v);
    pt_migrate(v);
}

void hvm_do_resume(struct vcpu *v)
{
    ioreq_t *p;

    pt_restore_timer(v);

    /* NB. Optimised for common case (p->state == STATE_IOREQ_NONE). */
    p = &get_ioreq(v)->vp_ioreq;
    while ( p->state != STATE_IOREQ_NONE )
    {
        switch ( p->state )
        {
        case STATE_IORESP_READY: /* IORESP_READY -> NONE */
            hvm_io_assist();
            break;
        case STATE_IOREQ_READY:  /* IOREQ_{READY,INPROCESS} -> IORESP_READY */
        case STATE_IOREQ_INPROCESS:
            wait_on_xen_event_channel(v->arch.hvm_vcpu.xen_port,
                                      (p->state != STATE_IOREQ_READY) &&
                                      (p->state != STATE_IOREQ_INPROCESS));
            break;
        default:
            gdprintk(XENLOG_ERR, "Weird HVM iorequest state %d.\n", p->state);
            domain_crash(v->domain);
            return; /* bail */
        }
    }
}

static void hvm_init_ioreq_page(
    struct domain *d, struct hvm_ioreq_page *iorp)
{
    memset(iorp, 0, sizeof(*iorp));
    spin_lock_init(&iorp->lock);
    domain_pause(d);
}

static void hvm_destroy_ioreq_page(
    struct domain *d, struct hvm_ioreq_page *iorp)
{
    spin_lock(&iorp->lock);

    ASSERT(d->is_dying);

    if ( iorp->va != NULL )
    {
        unmap_domain_page_global(iorp->va);
        put_page_and_type(iorp->page);
        iorp->va = NULL;
    }

    spin_unlock(&iorp->lock);
}

static int hvm_set_ioreq_page(
    struct domain *d, struct hvm_ioreq_page *iorp, unsigned long gmfn)
{
    struct page_info *page;
    p2m_type_t p2mt;
    unsigned long mfn;
    void *va;

    mfn = mfn_x(gfn_to_mfn(d, gmfn, &p2mt));
    if ( !p2m_is_ram(p2mt) )
        return -EINVAL;
    ASSERT(mfn_valid(mfn));

    page = mfn_to_page(mfn);
    if ( !get_page_and_type(page, d, PGT_writable_page) )
        return -EINVAL;

    va = map_domain_page_global(mfn);
    if ( va == NULL )
    {
        put_page_and_type(page);
        return -ENOMEM;
    }

    spin_lock(&iorp->lock);

    if ( (iorp->va != NULL) || d->is_dying )
    {
        spin_unlock(&iorp->lock);
        unmap_domain_page_global(va);
        put_page_and_type(mfn_to_page(mfn));
        return -EINVAL;
    }

    iorp->va = va;
    iorp->page = page;

    spin_unlock(&iorp->lock);

    domain_unpause(d);

    return 0;
}

static int hvm_print_line(
    int dir, uint32_t port, uint32_t bytes, uint32_t *val)
{
    struct vcpu *curr = current;
    struct hvm_domain *hd = &curr->domain->arch.hvm_domain;
    char c = *val;

    BUG_ON(bytes != 1);

    spin_lock(&hd->pbuf_lock);
    hd->pbuf[hd->pbuf_idx++] = c;
    if ( (hd->pbuf_idx == (sizeof(hd->pbuf) - 2)) || (c == '\n') )
    {
        if ( c != '\n' )
            hd->pbuf[hd->pbuf_idx++] = '\n';
        hd->pbuf[hd->pbuf_idx] = '\0';
        printk(XENLOG_G_DEBUG "HVM%u: %s", curr->domain->domain_id, hd->pbuf);
        hd->pbuf_idx = 0;
    }
    spin_unlock(&hd->pbuf_lock);

    return X86EMUL_OKAY;
}

int hvm_domain_initialise(struct domain *d)
{
    int rc;

    if ( !hvm_enabled )
    {
        gdprintk(XENLOG_WARNING, "Attempt to create a HVM guest "
                 "on a non-VT/AMDV platform.\n");
        return -EINVAL;
    }

    spin_lock_init(&d->arch.hvm_domain.pbuf_lock);
    spin_lock_init(&d->arch.hvm_domain.irq_lock);
    spin_lock_init(&d->arch.hvm_domain.uc_lock);

    hvm_init_guest_time(d);

    d->arch.hvm_domain.params[HVM_PARAM_HPET_ENABLED] = 1;

    hvm_init_cacheattr_region_list(d);

    rc = paging_enable(d, PG_refcounts|PG_translate|PG_external);
    if ( rc != 0 )
        goto fail1;

    vpic_init(d);

    rc = vioapic_init(d);
    if ( rc != 0 )
        goto fail1;

    stdvga_init(d);

    rtc_init(d);

    hvm_init_ioreq_page(d, &d->arch.hvm_domain.ioreq);
    hvm_init_ioreq_page(d, &d->arch.hvm_domain.buf_ioreq);

    register_portio_handler(d, 0xe9, 1, hvm_print_line);

    rc = hvm_funcs.domain_initialise(d);
    if ( rc != 0 )
        goto fail2;

    return 0;

 fail2:
    rtc_deinit(d);
    stdvga_deinit(d);
    vioapic_deinit(d);
 fail1:
    hvm_destroy_cacheattr_region_list(d);
    return rc;
}

void hvm_domain_relinquish_resources(struct domain *d)
{
    hvm_destroy_ioreq_page(d, &d->arch.hvm_domain.ioreq);
    hvm_destroy_ioreq_page(d, &d->arch.hvm_domain.buf_ioreq);

    /* Stop all asynchronous timer actions. */
    rtc_deinit(d);
    if ( d->vcpu[0] != NULL )
    {
        pit_deinit(d);
        pmtimer_deinit(d);
        hpet_deinit(d);
    }
}

void hvm_domain_destroy(struct domain *d)
{
    hvm_funcs.domain_destroy(d);
    rtc_deinit(d);
    stdvga_deinit(d);
    vioapic_deinit(d);
    hvm_destroy_cacheattr_region_list(d);
}

static int hvm_save_cpu_ctxt(struct domain *d, hvm_domain_context_t *h)
{
    struct vcpu *v;
    struct hvm_hw_cpu ctxt;
    struct segment_register seg;
    struct vcpu_guest_context *vc;

    for_each_vcpu ( d, v )
    {
        /* We don't need to save state for a vcpu that is down; the restore 
         * code will leave it down if there is nothing saved. */
        if ( test_bit(_VPF_down, &v->pause_flags) ) 
            continue;

        /* Architecture-specific vmcs/vmcb bits */
        hvm_funcs.save_cpu_ctxt(v, &ctxt);

        hvm_get_segment_register(v, x86_seg_idtr, &seg);
        ctxt.idtr_limit = seg.limit;
        ctxt.idtr_base = seg.base;

        hvm_get_segment_register(v, x86_seg_gdtr, &seg);
        ctxt.gdtr_limit = seg.limit;
        ctxt.gdtr_base = seg.base;

        hvm_get_segment_register(v, x86_seg_cs, &seg);
        ctxt.cs_sel = seg.sel;
        ctxt.cs_limit = seg.limit;
        ctxt.cs_base = seg.base;
        ctxt.cs_arbytes = seg.attr.bytes;

        hvm_get_segment_register(v, x86_seg_ds, &seg);
        ctxt.ds_sel = seg.sel;
        ctxt.ds_limit = seg.limit;
        ctxt.ds_base = seg.base;
        ctxt.ds_arbytes = seg.attr.bytes;

        hvm_get_segment_register(v, x86_seg_es, &seg);
        ctxt.es_sel = seg.sel;
        ctxt.es_limit = seg.limit;
        ctxt.es_base = seg.base;
        ctxt.es_arbytes = seg.attr.bytes;

        hvm_get_segment_register(v, x86_seg_ss, &seg);
        ctxt.ss_sel = seg.sel;
        ctxt.ss_limit = seg.limit;
        ctxt.ss_base = seg.base;
        ctxt.ss_arbytes = seg.attr.bytes;

        hvm_get_segment_register(v, x86_seg_fs, &seg);
        ctxt.fs_sel = seg.sel;
        ctxt.fs_limit = seg.limit;
        ctxt.fs_base = seg.base;
        ctxt.fs_arbytes = seg.attr.bytes;

        hvm_get_segment_register(v, x86_seg_gs, &seg);
        ctxt.gs_sel = seg.sel;
        ctxt.gs_limit = seg.limit;
        ctxt.gs_base = seg.base;
        ctxt.gs_arbytes = seg.attr.bytes;

        hvm_get_segment_register(v, x86_seg_tr, &seg);
        ctxt.tr_sel = seg.sel;
        ctxt.tr_limit = seg.limit;
        ctxt.tr_base = seg.base;
        ctxt.tr_arbytes = seg.attr.bytes;

        hvm_get_segment_register(v, x86_seg_ldtr, &seg);
        ctxt.ldtr_sel = seg.sel;
        ctxt.ldtr_limit = seg.limit;
        ctxt.ldtr_base = seg.base;
        ctxt.ldtr_arbytes = seg.attr.bytes;

        vc = &v->arch.guest_context;

        if ( v->fpu_initialised )
            memcpy(ctxt.fpu_regs, &vc->fpu_ctxt, sizeof(ctxt.fpu_regs));
        else 
            memset(ctxt.fpu_regs, 0, sizeof(ctxt.fpu_regs));

        ctxt.rax = vc->user_regs.eax;
        ctxt.rbx = vc->user_regs.ebx;
        ctxt.rcx = vc->user_regs.ecx;
        ctxt.rdx = vc->user_regs.edx;
        ctxt.rbp = vc->user_regs.ebp;
        ctxt.rsi = vc->user_regs.esi;
        ctxt.rdi = vc->user_regs.edi;
        ctxt.rsp = vc->user_regs.esp;
        ctxt.rip = vc->user_regs.eip;
        ctxt.rflags = vc->user_regs.eflags;
#ifdef __x86_64__
        ctxt.r8  = vc->user_regs.r8;