From 214d9bbcd3a67230b932f6cea83c078ab34d9e70 Mon Sep 17 00:00:00 2001 From: Claudio Imbrenda Date: Tue, 21 Jan 2020 09:48:44 +0100 Subject: s390/mm: provide memory management functions for protected KVM guests This provides the basic ultravisor calls and page table handling to cope with secure guests: - provide arch_make_page_accessible - make pages accessible after unmapping of secure guests - provide the ultravisor commands convert to/from secure - provide the ultravisor commands pin/unpin shared - provide callbacks to make pages secure (inacccessible) - we check for the expected pin count to only make pages secure if the host is not accessing them - we fence hugetlbfs for secure pages - add missing radix-tree include into gmap.h The basic idea is that a page can have 3 states: secure, normal or shared. The hypervisor can call into a firmware function called ultravisor that allows to change the state of a page: convert from/to secure. The convert from secure will encrypt the page and make it available to the host and host I/O. The convert to secure will remove the host capability to access this page. The design is that on convert to secure we will wait until writeback and page refs are indicating no host usage. At the same time the convert from secure (export to host) will be called in common code when the refcount or the writeback bit is already set. This avoids races between convert from and to secure. Then there is also the concept of shared pages. Those are kind of secure where the host can still access those pages. We need to be notified when the guest "unshares" such a page, basically doing a convert to secure by then. There is a call "pin shared page" that we use instead of convert from secure when possible. We do use PG_arch_1 as an optimization to minimize the convert from secure/pin shared. Several comments have been added in the code to explain the logic in the relevant places. Co-developed-by: Ulrich Weigand Signed-off-by: Ulrich Weigand Signed-off-by: Claudio Imbrenda Acked-by: David Hildenbrand Acked-by: Cornelia Huck Reviewed-by: Christian Borntraeger [borntraeger@de.ibm.com: patch merging, splitting, fixing] Signed-off-by: Christian Borntraeger --- arch/s390/include/asm/gmap.h | 4 ++++ 1 file changed, 4 insertions(+) (limited to 'arch/s390/include/asm/gmap.h') diff --git a/arch/s390/include/asm/gmap.h b/arch/s390/include/asm/gmap.h index 37f96b6f0e61..3c4926aa78f4 100644 --- a/arch/s390/include/asm/gmap.h +++ b/arch/s390/include/asm/gmap.h @@ -9,6 +9,7 @@ #ifndef _ASM_S390_GMAP_H #define _ASM_S390_GMAP_H +#include #include /* Generic bits for GMAP notification on DAT table entry changes. */ @@ -31,6 +32,7 @@ * @table: pointer to the page directory * @asce: address space control element for gmap page table * @pfault_enabled: defines if pfaults are applicable for the guest + * @guest_handle: protected virtual machine handle for the ultravisor * @host_to_rmap: radix tree with gmap_rmap lists * @children: list of shadow gmap structures * @pt_list: list of all page tables used in the shadow guest address space @@ -54,6 +56,8 @@ struct gmap { unsigned long asce_end; void *private; bool pfault_enabled; + /* only set for protected virtual machines */ + unsigned long guest_handle; /* Additional data for shadow guest address spaces */ struct radix_tree_root host_to_rmap; struct list_head children; -- cgit