From: Quentin Perret Date: Mon, 9 Aug 2021 15:24:39 +0000 (+0100) Subject: KVM: arm64: Add helpers to tag shared pages in SW bits X-Git-Tag: v5.15-rc1~65^2~4^2~5^2~13 X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=ec250a67ea8db6209918a389554cf3aec0395b1f;p=thirdparty%2Fkernel%2Flinux.git 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: Fuad Tabba Signed-off-by: Quentin Perret Signed-off-by: Marc Zyngier Link: https://lore.kernel.org/r/20210809152448.1810400-13-qperret@google.com --- diff --git a/arch/arm64/kvm/hyp/include/nvhe/mem_protect.h b/arch/arm64/kvm/hyp/include/nvhe/mem_protect.h index 9c227d87c36d3..87b1690c439fc 100644 --- a/arch/arm64/kvm/hyp/include/nvhe/mem_protect.h +++ b/arch/arm64/kvm/hyp/include/nvhe/mem_protect.h @@ -12,6 +12,32 @@ #include #include +/* + * 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;