When dm_restrict is set, QEMU isn't permitted to update the XenStore node
to indicate its running status. Previously, the xs_write() call would fail
but the failure was ignored.
However, in refactoring to allow for emulated XenStore operations, a new
call to xs_open() was added. That one didn't fail gracefully, causing a
fatal error when running in dm_restrict mode.
Partially revert the offending patch, removing the additional call to
xs_open() because the global 'xenstore' variable is still available; it
just needs to be used with qemu_xen_xs_write() now instead of directly
with the xs_write() libxenstore function.
Also make the whole thing conditional on !xen_domid_restrict. There's no
point even registering the state change handler to attempt to update the
XenStore node when we know it's destined to fail.
Fixes: ba2a92db1ff6 ("hw/xen: Add xenstore operations to allow redirection to internal emulation")
Reported-by: Jason Andryuk <jandryuk@gmail.com>
Co-developed-by: Jason Andryuk <jandryuk@gmail.com>
Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>
Reviewed-by: Paul Durrant <paul@xen.org>
Tested-by: Jason Andryuk <jandryuk@gmail.com>
Message-Id: <1f141995bb61af32c2867ef5559e253f39b0949c.camel@infradead.org>
Signed-off-by: Anthony PERARD <anthony.perard@citrix.com>
		
	
			
		
			
				
	
	
		
			169 lines
		
	
	
		
			4.4 KiB
		
	
	
	
		
			C
		
	
	
	
	
	
			
		
		
	
	
			169 lines
		
	
	
		
			4.4 KiB
		
	
	
	
		
			C
		
	
	
	
	
	
/*
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 * Copyright (C) 2014       Citrix Systems UK Ltd.
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 *
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 * This work is licensed under the terms of the GNU GPL, version 2.  See
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 * the COPYING file in the top-level directory.
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 *
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 * Contributions after 2012-01-13 are licensed under the terms of the
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 * GNU GPL, version 2 or (at your option) any later version.
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 */
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#include "qemu/osdep.h"
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#include "qemu/error-report.h"
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#include "qemu/module.h"
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#include "qapi/error.h"
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#include "hw/xen/xen_native.h"
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#include "hw/xen/xen-legacy-backend.h"
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#include "hw/xen/xen_pt.h"
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#include "chardev/char.h"
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#include "qemu/accel.h"
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#include "sysemu/cpus.h"
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#include "sysemu/xen.h"
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#include "sysemu/runstate.h"
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#include "migration/misc.h"
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#include "migration/global_state.h"
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#include "hw/boards.h"
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bool xen_allowed;
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xc_interface *xen_xc;
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xenforeignmemory_handle *xen_fmem;
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xendevicemodel_handle *xen_dmod;
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static void xenstore_record_dm_state(const char *state)
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{
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    char path[50];
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    snprintf(path, sizeof (path), "device-model/%u/state", xen_domid);
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    if (!qemu_xen_xs_write(xenstore, XBT_NULL, path, state, strlen(state))) {
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        error_report("error recording dm state");
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        exit(1);
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    }
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}
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static void xen_change_state_handler(void *opaque, bool running,
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                                     RunState state)
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{
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    if (running) {
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        /* record state running */
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        xenstore_record_dm_state("running");
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    }
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}
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static bool xen_get_igd_gfx_passthru(Object *obj, Error **errp)
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{
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    return xen_igd_gfx_pt_enabled();
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}
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static void xen_set_igd_gfx_passthru(Object *obj, bool value, Error **errp)
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{
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    xen_igd_gfx_pt_set(value, errp);
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}
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static void xen_setup_post(MachineState *ms, AccelState *accel)
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{
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    int rc;
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    if (xen_domid_restrict) {
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        rc = xen_restrict(xen_domid);
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        if (rc < 0) {
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            perror("xen: failed to restrict");
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            exit(1);
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        }
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    }
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}
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static int xen_init(MachineState *ms)
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{
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    MachineClass *mc = MACHINE_GET_CLASS(ms);
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    xen_xc = xc_interface_open(0, 0, 0);
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    if (xen_xc == NULL) {
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        xen_pv_printf(NULL, 0, "can't open xen interface\n");
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        return -1;
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    }
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    xen_fmem = xenforeignmemory_open(0, 0);
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    if (xen_fmem == NULL) {
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        xen_pv_printf(NULL, 0, "can't open xen fmem interface\n");
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        xc_interface_close(xen_xc);
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        return -1;
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    }
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    xen_dmod = xendevicemodel_open(0, 0);
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    if (xen_dmod == NULL) {
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        xen_pv_printf(NULL, 0, "can't open xen devicemodel interface\n");
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        xenforeignmemory_close(xen_fmem);
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        xc_interface_close(xen_xc);
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        return -1;
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    }
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    /*
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     * The XenStore write would fail when running restricted so don't attempt
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     * it in that case. Toolstacks should instead use QMP to listen for state
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     * changes.
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     */
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    if (!xen_domid_restrict) {
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        qemu_add_vm_change_state_handler(xen_change_state_handler, NULL);
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    }
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    /*
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     * opt out of system RAM being allocated by generic code
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     */
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    mc->default_ram_id = NULL;
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    xen_mode = XEN_ATTACH;
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    return 0;
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}
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static void xen_accel_class_init(ObjectClass *oc, void *data)
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{
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    AccelClass *ac = ACCEL_CLASS(oc);
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    static GlobalProperty compat[] = {
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        { "migration", "store-global-state", "off" },
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        { "migration", "send-configuration", "off" },
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        { "migration", "send-section-footer", "off" },
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    };
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    ac->name = "Xen";
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    ac->init_machine = xen_init;
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    ac->setup_post = xen_setup_post;
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    ac->allowed = &xen_allowed;
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    ac->compat_props = g_ptr_array_new();
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    compat_props_add(ac->compat_props, compat, G_N_ELEMENTS(compat));
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    object_class_property_add_bool(oc, "igd-passthru",
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        xen_get_igd_gfx_passthru, xen_set_igd_gfx_passthru);
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    object_class_property_set_description(oc, "igd-passthru",
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        "Set on/off to enable/disable igd passthrou");
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}
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#define TYPE_XEN_ACCEL ACCEL_CLASS_NAME("xen")
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static const TypeInfo xen_accel_type = {
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    .name = TYPE_XEN_ACCEL,
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    .parent = TYPE_ACCEL,
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    .class_init = xen_accel_class_init,
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};
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static void xen_accel_ops_class_init(ObjectClass *oc, void *data)
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{
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    AccelOpsClass *ops = ACCEL_OPS_CLASS(oc);
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    ops->create_vcpu_thread = dummy_start_vcpu_thread;
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}
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static const TypeInfo xen_accel_ops_type = {
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    .name = ACCEL_OPS_NAME("xen"),
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    .parent = TYPE_ACCEL_OPS,
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    .class_init = xen_accel_ops_class_init,
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    .abstract = true,
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};
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static void xen_type_init(void)
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{
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    type_register_static(&xen_accel_type);
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    type_register_static(&xen_accel_ops_type);
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}
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type_init(xen_type_init);
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