Example #1
0
static int hvmemul_do_mmio(
    paddr_t gpa, unsigned long *reps, int size,
    paddr_t ram_gpa, int dir, int df, void *p_data)
{
    return hvmemul_do_io(1, gpa, reps, size, ram_gpa, dir, df, p_data);
}
Example #2
0
static int hvmemul_do_io(
    int is_mmio, paddr_t addr, unsigned long *reps, int size,
    paddr_t ram_gpa, int dir, int df, void *p_data)
{
    struct vcpu *curr = current;
    struct hvm_vcpu_io *vio;
    ioreq_t p = {
        .type = is_mmio ? IOREQ_TYPE_COPY : IOREQ_TYPE_PIO,
        .addr = addr,
        .size = size,
        .dir = dir,
        .df = df,
        .data = ram_gpa,
        .data_is_ptr = (p_data == NULL),
    };
    unsigned long ram_gfn = paddr_to_pfn(ram_gpa);
    p2m_type_t p2mt;
    struct page_info *ram_page;
    int rc;

    /* Check for paged out page */
    ram_page = get_page_from_gfn(curr->domain, ram_gfn, &p2mt, P2M_UNSHARE);
    if ( p2m_is_paging(p2mt) )
    {
        if ( ram_page )
            put_page(ram_page);
        p2m_mem_paging_populate(curr->domain, ram_gfn);
        return X86EMUL_RETRY;
    }
    if ( p2m_is_shared(p2mt) )
    {
        if ( ram_page )
            put_page(ram_page);
        return X86EMUL_RETRY;
    }

    /*
     * Weird-sized accesses have undefined behaviour: we discard writes
     * and read all-ones.
     */
    if ( unlikely((size > sizeof(long)) || (size & (size - 1))) )
    {
        gdprintk(XENLOG_WARNING, "bad mmio size %d\n", size);
        ASSERT(p_data != NULL); /* cannot happen with a REP prefix */
        if ( dir == IOREQ_READ )
            memset(p_data, ~0, size);
        if ( ram_page )
            put_page(ram_page);
        return X86EMUL_UNHANDLEABLE;
    }

    if ( !p.data_is_ptr && (dir == IOREQ_WRITE) )
    {
        memcpy(&p.data, p_data, size);
        p_data = NULL;
    }

    vio = &curr->arch.hvm_vcpu.hvm_io;

    if ( is_mmio && !p.data_is_ptr )
    {
        /* Part of a multi-cycle read or write? */
        if ( dir == IOREQ_WRITE )
        {
            paddr_t pa = vio->mmio_large_write_pa;
            unsigned int bytes = vio->mmio_large_write_bytes;
            if ( (addr >= pa) && ((addr + size) <= (pa + bytes)) )
            {
                if ( ram_page )
                    put_page(ram_page);
                return X86EMUL_OKAY;
            }
        }
        else
        {
            paddr_t pa = vio->mmio_large_read_pa;
            unsigned int bytes = vio->mmio_large_read_bytes;
            if ( (addr >= pa) && ((addr + size) <= (pa + bytes)) )
            {
                memcpy(p_data, &vio->mmio_large_read[addr - pa],
                       size);
                if ( ram_page )
                    put_page(ram_page);
                return X86EMUL_OKAY;
            }
        }
    }

    switch ( vio->io_state )
    {
    case HVMIO_none:
        break;
    case HVMIO_completed:
        vio->io_state = HVMIO_none;
        if ( p_data == NULL )
        {
            if ( ram_page )
                put_page(ram_page);
            return X86EMUL_UNHANDLEABLE;
        }
        goto finish_access;
    case HVMIO_dispatched:
        /* May have to wait for previous cycle of a multi-write to complete. */
        if ( is_mmio && !p.data_is_ptr && (dir == IOREQ_WRITE) &&
             (addr == (vio->mmio_large_write_pa +
                       vio->mmio_large_write_bytes)) )
        {
            if ( ram_page )
                put_page(ram_page);
            return X86EMUL_RETRY;
        }
    default:
        if ( ram_page )
            put_page(ram_page);
        return X86EMUL_UNHANDLEABLE;
    }

    if ( hvm_io_pending(curr) )
    {
        gdprintk(XENLOG_WARNING, "WARNING: io already pending?\n");
        if ( ram_page )
            put_page(ram_page);
        return X86EMUL_UNHANDLEABLE;
    }

    vio->io_state =
        (p_data == NULL) ? HVMIO_dispatched : HVMIO_awaiting_completion;
    vio->io_size = size;

    /*
     * When retrying a repeated string instruction, force exit to guest after
     * completion of the retried iteration to allow handling of interrupts.
     */
    if ( vio->mmio_retrying )
        *reps = 1;

    p.count = *reps;

    if ( dir == IOREQ_WRITE )
        hvmtrace_io_assist(is_mmio, &p);

    if ( is_mmio )
    {
        rc = hvm_mmio_intercept(&p);
        if ( rc == X86EMUL_UNHANDLEABLE )
            rc = hvm_buffered_io_intercept(&p);
    }
    else
    {
        rc = hvm_portio_intercept(&p);
    }

    switch ( rc )
    {
    case X86EMUL_OKAY:
    case X86EMUL_RETRY:
        *reps = p.count;
        p.state = STATE_IORESP_READY;
        if ( !vio->mmio_retry )
        {
            hvm_io_assist(&p);
            vio->io_state = HVMIO_none;
        }
        else
            /* Defer hvm_io_assist() invocation to hvm_do_resume(). */
            vio->io_state = HVMIO_handle_mmio_awaiting_completion;
        break;
    case X86EMUL_UNHANDLEABLE:
        /* If there is no backing DM, just ignore accesses */
        if ( !hvm_has_dm(curr->domain) )
        {
            rc = X86EMUL_OKAY;
            vio->io_state = HVMIO_none;
        }
        else
        {
            rc = X86EMUL_RETRY;
            if ( !hvm_send_assist_req(&p) )
                vio->io_state = HVMIO_none;
            else if ( p_data == NULL )
                rc = X86EMUL_OKAY;
        }
        break;
    default:
        BUG();
    }

    if ( rc != X86EMUL_OKAY )
    {
        if ( ram_page )
            put_page(ram_page);
        return rc;
    }

 finish_access:
    if ( dir == IOREQ_READ )
        hvmtrace_io_assist(is_mmio, &p);

    if ( p_data != NULL )
        memcpy(p_data, &vio->io_data, size);

    if ( is_mmio && !p.data_is_ptr )
    {
        /* Part of a multi-cycle read or write? */
        if ( dir == IOREQ_WRITE )
        {
            paddr_t pa = vio->mmio_large_write_pa;
            unsigned int bytes = vio->mmio_large_write_bytes;
            if ( bytes == 0 )
                pa = vio->mmio_large_write_pa = addr;
            if ( addr == (pa + bytes) )
                vio->mmio_large_write_bytes += size;
        }
        else
        {
            paddr_t pa = vio->mmio_large_read_pa;
            unsigned int bytes = vio->mmio_large_read_bytes;
            if ( bytes == 0 )
                pa = vio->mmio_large_read_pa = addr;
            if ( (addr == (pa + bytes)) &&
                 ((bytes + size) <= sizeof(vio->mmio_large_read)) )
            {
                memcpy(&vio->mmio_large_read[bytes], p_data, size);
                vio->mmio_large_read_bytes += size;
            }
        }
    }

    if ( ram_page )
        put_page(ram_page);
    return X86EMUL_OKAY;
}

int hvmemul_do_pio(
    unsigned long port, unsigned long *reps, int size,
    paddr_t ram_gpa, int dir, int df, void *p_data)
{
    return hvmemul_do_io(0, port, reps, size, ram_gpa, dir, df, p_data);
}

static int hvmemul_do_mmio(
    paddr_t gpa, unsigned long *reps, int size,
    paddr_t ram_gpa, int dir, int df, void *p_data)
{
    return hvmemul_do_io(1, gpa, reps, size, ram_gpa, dir, df, p_data);
}

/*
 * Convert addr from linear to physical form, valid over the range
 * [addr, addr + *reps * bytes_per_rep]. *reps is adjusted according to
 * the valid computed range. It is always >0 when X86EMUL_OKAY is returned.
 * @pfec indicates the access checks to be performed during page-table walks.
 */
static int hvmemul_linear_to_phys(
    unsigned long addr,
    paddr_t *paddr,
    unsigned int bytes_per_rep,
    unsigned long *reps,
    uint32_t pfec,
    struct hvm_emulate_ctxt *hvmemul_ctxt)
{
    struct vcpu *curr = current;
    unsigned long pfn, npfn, done, todo, i, offset = addr & ~PAGE_MASK;
    int reverse;

    /*
     * Clip repetitions to a sensible maximum. This avoids extensive looping in
     * this function while still amortising the cost of I/O trap-and-emulate.
     */
    *reps = min_t(unsigned long, *reps, 4096);

    /* With no paging it's easy: linear == physical. */
    if ( !(curr->arch.hvm_vcpu.guest_cr[0] & X86_CR0_PG) )
    {
        *paddr = addr;
        return X86EMUL_OKAY;
    }

    /* Reverse mode if this is a backwards multi-iteration string operation. */
    reverse = (hvmemul_ctxt->ctxt.regs->eflags & X86_EFLAGS_DF) && (*reps > 1);

    if ( reverse && ((PAGE_SIZE - offset) < bytes_per_rep) )
    {
        /* Do page-straddling first iteration forwards via recursion. */
        paddr_t _paddr;
        unsigned long one_rep = 1;
        int rc = hvmemul_linear_to_phys(
            addr, &_paddr, bytes_per_rep, &one_rep, pfec, hvmemul_ctxt);
        if ( rc != X86EMUL_OKAY )
            return rc;
        pfn = _paddr >> PAGE_SHIFT;
    }
    else if ( (pfn = paging_gva_to_gfn(curr, addr, &pfec)) == INVALID_GFN )
Example #3
0
int hvmemul_do_pio(
    unsigned long port, unsigned long *reps, int size,
    paddr_t ram_gpa, int dir, int df, void *p_data)
{
    return hvmemul_do_io(0, port, reps, size, ram_gpa, dir, df, p_data);
}