Commit 5ac14bac authored by Claudio Imbrenda's avatar Claudio Imbrenda Committed by Christian Borntraeger
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KVM: s390: extend kvm_s390_shadow_fault to return entry pointer 



Extend kvm_s390_shadow_fault to return the pointer to the valid leaf
DAT table entry, or to the invalid entry.

Also return some flags in the lower bits of the address:
PEI_DAT_PROT: indicates that DAT protection applies because of the
              protection bit in the segment (or, if EDAT, region) tables.
PEI_NOT_PTE: indicates that the address of the DAT table entry returned
             does not refer to a PTE, but to a segment or region table.

Signed-off-by: default avatarClaudio Imbrenda <imbrenda@linux.ibm.com>
Cc: stable@vger.kernel.org
Reviewed-by: default avatarJanosch Frank <frankja@de.ibm.com>
Reviewed-by: default avatarDavid Hildenbrand <david@redhat.com>
Reviewed-by: default avatarChristian Borntraeger <borntraeger@de.ibm.com>
Link: https://lore.kernel.org/r/20210302174443.514363-3-imbrenda@linux.ibm.com


[borntraeger@de.ibm.com: fold in a fix from Claudio]
Signed-off-by: default avatarChristian Borntraeger <borntraeger@de.ibm.com>
parent f85f1baa

arch/s390/kvm/gaccess.c

+25 −5
Original line number Diff line number Diff line
@@ -976,7 +976,9 @@ int kvm_s390_check_low_addr_prot_real(struct kvm_vcpu *vcpu, unsigned long gra) 
 * kvm_s390_shadow_tables - walk the guest page table and create shadow tables

 * @sg: pointer to the shadow guest address space structure

 * @saddr: faulting address in the shadow gmap

 * @pgt: pointer to the page table address result

 * @pgt: pointer to the beginning of the page table for the given address if

 *	 successful (return value 0), or to the first invalid DAT entry in

 *	 case of exceptions (return value > 0)

 * @fake: pgt references contiguous guest memory block, not a pgtable

 */

static int kvm_s390_shadow_tables(struct gmap *sg, unsigned long saddr,
@@ -1034,6 +1036,7 @@ static int kvm_s390_shadow_tables(struct gmap *sg, unsigned long saddr, 
			rfte.val = ptr;

			goto shadow_r2t;

		}

		*pgt = ptr + vaddr.rfx * 8;

		rc = gmap_read_table(parent, ptr + vaddr.rfx * 8, &rfte.val);

		if (rc)

			return rc;
@@ -1060,6 +1063,7 @@ static int kvm_s390_shadow_tables(struct gmap *sg, unsigned long saddr, 
			rste.val = ptr;

			goto shadow_r3t;

		}

		*pgt = ptr + vaddr.rsx * 8;

		rc = gmap_read_table(parent, ptr + vaddr.rsx * 8, &rste.val);

		if (rc)

			return rc;
@@ -1087,6 +1091,7 @@ static int kvm_s390_shadow_tables(struct gmap *sg, unsigned long saddr, 
			rtte.val = ptr;

			goto shadow_sgt;

		}

		*pgt = ptr + vaddr.rtx * 8;

		rc = gmap_read_table(parent, ptr + vaddr.rtx * 8, &rtte.val);

		if (rc)

			return rc;
@@ -1123,6 +1128,7 @@ static int kvm_s390_shadow_tables(struct gmap *sg, unsigned long saddr, 
			ste.val = ptr;

			goto shadow_pgt;

		}

		*pgt = ptr + vaddr.sx * 8;

		rc = gmap_read_table(parent, ptr + vaddr.sx * 8, &ste.val);

		if (rc)

			return rc;
@@ -1157,6 +1163,8 @@ static int kvm_s390_shadow_tables(struct gmap *sg, unsigned long saddr, 
 * @vcpu: virtual cpu

 * @sg: pointer to the shadow guest address space structure

 * @saddr: faulting address in the shadow gmap

 * @datptr: will contain the address of the faulting DAT table entry, or of

 *	    the valid leaf, plus some flags

 *

 * Returns: - 0 if the shadow fault was successfully resolved

 *	    - > 0 (pgm exception code) on exceptions while faulting
@@ -1165,11 +1173,11 @@ static int kvm_s390_shadow_tables(struct gmap *sg, unsigned long saddr, 
 *	    - -ENOMEM if out of memory

 */

int kvm_s390_shadow_fault(struct kvm_vcpu *vcpu, struct gmap *sg,

			  unsigned long saddr)

			  unsigned long saddr, unsigned long *datptr)

{

	union vaddress vaddr;

	union page_table_entry pte;

	unsigned long pgt;

	unsigned long pgt = 0;

	int dat_protection, fake;

	int rc;
@@ -1191,8 +1199,20 @@ int kvm_s390_shadow_fault(struct kvm_vcpu *vcpu, struct gmap *sg, 
		pte.val = pgt + vaddr.px * PAGE_SIZE;

		goto shadow_page;

	}

	if (!rc)

		rc = gmap_read_table(sg->parent, pgt + vaddr.px * 8, &pte.val);



	switch (rc) {

	case PGM_SEGMENT_TRANSLATION:

	case PGM_REGION_THIRD_TRANS:

	case PGM_REGION_SECOND_TRANS:

	case PGM_REGION_FIRST_TRANS:

		pgt |= PEI_NOT_PTE;

		break;

	case 0:

		pgt += vaddr.px * 8;

		rc = gmap_read_table(sg->parent, pgt, &pte.val);

	}

	if (datptr)

		*datptr = pgt | dat_protection * PEI_DAT_PROT;

	if (!rc && pte.i)

		rc = PGM_PAGE_TRANSLATION;

	if (!rc && pte.z)

arch/s390/kvm/gaccess.h

+5 −1
Original line number Diff line number Diff line
@@ -376,7 +376,11 @@ void ipte_unlock(struct kvm_vcpu *vcpu); 
int ipte_lock_held(struct kvm_vcpu *vcpu);

int kvm_s390_check_low_addr_prot_real(struct kvm_vcpu *vcpu, unsigned long gra);



/* MVPG PEI indication bits */

#define PEI_DAT_PROT 2

#define PEI_NOT_PTE 4



int kvm_s390_shadow_fault(struct kvm_vcpu *vcpu, struct gmap *shadow,

			  unsigned long saddr);

			  unsigned long saddr, unsigned long *datptr);



#endif /* __KVM_S390_GACCESS_H */

arch/s390/kvm/vsie.c

+4 −4
Original line number Diff line number Diff line
@@ -620,10 +620,10 @@ static int map_prefix(struct kvm_vcpu *vcpu, struct vsie_page *vsie_page) 
	/* with mso/msl, the prefix lies at offset *mso* */

	prefix += scb_s->mso;



	rc = kvm_s390_shadow_fault(vcpu, vsie_page->gmap, prefix);

	rc = kvm_s390_shadow_fault(vcpu, vsie_page->gmap, prefix, NULL);

	if (!rc && (scb_s->ecb & ECB_TE))

		rc = kvm_s390_shadow_fault(vcpu, vsie_page->gmap,

					   prefix + PAGE_SIZE);

					   prefix + PAGE_SIZE, NULL);

	/*

	 * We don't have to mprotect, we will be called for all unshadows.

	 * SIE will detect if protection applies and trigger a validity.
@@ -914,7 +914,7 @@ static int handle_fault(struct kvm_vcpu *vcpu, struct vsie_page *vsie_page) 
				    current->thread.gmap_addr, 1);



	rc = kvm_s390_shadow_fault(vcpu, vsie_page->gmap,

				   current->thread.gmap_addr);

				   current->thread.gmap_addr, NULL);

	if (rc > 0) {

		rc = inject_fault(vcpu, rc,

				  current->thread.gmap_addr,
@@ -936,7 +936,7 @@ static void handle_last_fault(struct kvm_vcpu *vcpu, 
{

	if (vsie_page->fault_addr)

		kvm_s390_shadow_fault(vcpu, vsie_page->gmap,

				      vsie_page->fault_addr);

				      vsie_page->fault_addr, NULL);

	vsie_page->fault_addr = 0;

}