genode/ports/include/vmm/guest_memory.h
Norman Feske 1df48b8331 ports: common utilities for building VMMs on NOVA
To ease the creation of custom virtual machine monitors on top of
NOVA, this patch moves generic utilities from vancouver resp. seoul to the
public include location 'ports/include/vmm'. As a nice side effect,
this change simplifies 'vancouver/main.cc'.

Issue #949
2013-11-25 12:12:31 +01:00

96 lines
2.5 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 <os/attached_ram_dataspace.h>
#include <rm_session/connection.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 : Rm_connection
{
Virtual_reservation(addr_t vm_size)
:
Rm_connection(0, vm_size)
{
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_session()->attach_at(Rm_connection::dataspace(),
PAGE_SIZE, 0, PAGE_SIZE);
} catch (Rm_session::Region_conflict) {
PERR("region conflict while attaching guest-physical memory");
}
}
~Virtual_reservation()
{
env()->rm_session()->detach((void *)PAGE_SIZE);
}
};
/**
* Representation of guest memory
*
*/
struct Vmm::Guest_memory : Attached_ram_dataspace
{
/**
* Constructor
*
* \param backing_store_size number of bytes of physical RAM to be
* used as guest-physical and device memory,
* allocated from core's RAM service
*/
Guest_memory(size_t backing_store_size)
:
Attached_ram_dataspace(env()->ram_session(), backing_store_size)
{ }
};
#endif /* _INCLUDE__VMM__GUEST_MEMORY_H_ */