genode/repos/ports/include/vmm/guest_memory.h
2017-01-13 13:07:04 +01:00

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 Genode Labs GmbH
*
* This file is part of the Genode OS framework, which is distributed
* under the terms of the GNU General Public License version 2.
*/
#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 (Rm_session::Region_conflict) {
error("region conflict while attaching guest-physical memory");
}
}
~Virtual_reservation()
{
_env.rm().detach((void *)PAGE_SIZE);
}
};
#endif /* _INCLUDE__VMM__GUEST_MEMORY_H_ */