genode/repos/ports/include/vmm/guest_memory.h
Norman Feske 4d442bca30 Streamline exception types
This patch reduces the number of exception types by facilitating
globally defined exceptions for common usage patterns shared by most
services. In particular, RPC functions that demand a session-resource
upgrade not longer reflect this condition via a session-specific
exception but via the 'Out_of_ram' or 'Out_of_caps' types.

Furthermore, the 'Parent::Service_denied', 'Parent::Unavailable',
'Root::Invalid_args', 'Root::Unavailable', 'Service::Invalid_args',
'Service::Unavailable', and 'Local_service::Factory::Denied' types have
been replaced by the single 'Service_denied' exception type defined in
'session/session.h'.

This consolidation eases the error handling (there are fewer exceptions
to handle), alleviates the need to convert exceptions along the
session-creation call chain, and avoids possible aliasing problems
(catching the wrong type with the same name but living in a different
scope).
2017-05-31 13:16:07 +02:00

82 lines
2.2 KiB
C++

/*
* \brief Utilities for implementing VMMs on Genode/NOVA
* \author Norman Feske
* \date 2013-08-20
*
* The VMM and the guest share the same PD. However, the guest's view on the PD
* is restricted to the guest-physical-to-VMM-local mappings installed by the
* VMM for the VCPU's EC.
*
* The guest memory is shadowed at the lower portion of the VMM's address
* space. If the guest (the VCPU EC) tries to access a page that has no mapping
* in the VMM's PD, NOVA does not generate a page-fault (which would be
* delivered to the pager of the VMM, i.e., core) but it produces a NPT
* virtualization event handled locally by the VMM. The NPT event handler is
* the '_svm_npt' function.
*/
/*
* Copyright (C) 2013-2017 Genode Labs GmbH
*
* This file is part of the Genode OS framework, which is distributed
* under the terms of the GNU Affero General Public License version 3.
*/
#ifndef _INCLUDE__VMM__GUEST_MEMORY_H_
#define _INCLUDE__VMM__GUEST_MEMORY_H_
/* Genode includes */
#include <base/attached_ram_dataspace.h>
#include <base/env.h>
#include <rm_session/connection.h>
#include <region_map/client.h>
/* VMM utilities includes */
#include <vmm/types.h>
namespace Vmm {
using namespace Genode;
class Virtual_reservation;
class Guest_memory;
}
/**
* The 'Virtual_reservation' is a managed dataspace that occupies the lower
* part of the address space, which contains the shadow of the VCPU's physical
* memory.
*/
struct Vmm::Virtual_reservation : private Rm_connection, Region_map_client
{
Genode::Env &_env;
Virtual_reservation(Genode::Env &env, addr_t vm_size)
:
Rm_connection(env),
Region_map_client(Rm_connection::create(vm_size)),
_env(env)
{
try {
/*
* Attach reservation to the beginning of the local address
* space. We leave out the very first page because core denies
* the attachment of anything at the zero page.
*/
env.rm().attach_at(Region_map_client::dataspace(), PAGE_SIZE, 0,
PAGE_SIZE);
} catch (Region_map::Region_conflict) {
error("region conflict while attaching guest-physical memory");
}
}
~Virtual_reservation()
{
_env.rm().detach((void *)PAGE_SIZE);
}
};
#endif /* _INCLUDE__VMM__GUEST_MEMORY_H_ */