Commit ec250a67 authored by Quentin Perret's avatar Quentin Perret Committed by Marc Zyngier
Browse files

KVM: arm64: Add helpers to tag shared pages in SW bits 



We will soon start annotating shared pages in page-tables in nVHE
protected mode. Define all the states in which a page can be (owned,
shared and owned, shared and borrowed), and provide helpers allowing to
convert this into SW bits annotations using the matching prot
attributes.

Reviewed-by: default avatarFuad Tabba <tabba@google.com>
Signed-off-by: default avatarQuentin Perret <qperret@google.com>
Signed-off-by: default avatarMarc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20210809152448.1810400-13-qperret@google.com
parent 4505e9b6

arch/arm64/kvm/hyp/include/nvhe/mem_protect.h

+26 −0
Original line number Diff line number Diff line
@@ -12,6 +12,32 @@ 
#include <asm/virt.h>

#include <nvhe/spinlock.h>



/*

 * SW bits 0-1 are reserved to track the memory ownership state of each page:

 *   00: The page is owned exclusively by the page-table owner.

 *   01: The page is owned by the page-table owner, but is shared

 *       with another entity.

 *   10: The page is shared with, but not owned by the page-table owner.

 *   11: Reserved for future use (lending).

 */

enum pkvm_page_state {

	PKVM_PAGE_OWNED			= 0ULL,

	PKVM_PAGE_SHARED_OWNED		= KVM_PGTABLE_PROT_SW0,

	PKVM_PAGE_SHARED_BORROWED	= KVM_PGTABLE_PROT_SW1,

};



#define PKVM_PAGE_STATE_PROT_MASK	(KVM_PGTABLE_PROT_SW0 | KVM_PGTABLE_PROT_SW1)

static inline enum kvm_pgtable_prot pkvm_mkstate(enum kvm_pgtable_prot prot,

						 enum pkvm_page_state state)

{

	return (prot & ~PKVM_PAGE_STATE_PROT_MASK) | state;

}



static inline enum pkvm_page_state pkvm_getstate(enum kvm_pgtable_prot prot)

{

	return prot & PKVM_PAGE_STATE_PROT_MASK;

}



struct host_kvm {

	struct kvm_arch arch;

	struct kvm_pgtable pgt;