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Commit addb63c1 authored by Heiko Carstens's avatar Heiko Carstens Committed by Christian Borntraeger
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KVM: s390: gaccess: fix real-space designation asce handling for gmap shadows 



For real-space designation asces the asce origin part is only a token.
The asce token origin must not be used to generate an effective
address for storage references. This however is erroneously done
within kvm_s390_shadow_tables().

Furthermore within the same function the wrong parts of virtual
addresses are used to generate a corresponding real address
(e.g. the region second index is used as region first index).

Both of the above can result in incorrect address translations. Only
for real space designations with a token origin of zero and addresses
below one megabyte the translation was correct.

Furthermore replace a "!asce.r" statement with a "!*fake" statement to
make it more obvious that a specific condition has nothing to do with
the architecture, but with the fake handling of real space designations.

Fixes: 3218f709 ("s390/mm: support real-space for gmap shadows")
Cc: David Hildenbrand <david@redhat.com>
Cc: stable@vger.kernel.org
Signed-off-by: default avatarHeiko Carstens <heiko.carstens@de.ibm.com>
Reviewed-by: default avatarMartin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: default avatarChristian Borntraeger <borntraeger@de.ibm.com>
parent 1ba15b24

arch/s390/kvm/gaccess.c

+6 −9
Original line number Diff line number Diff line
@@ -977,11 +977,12 @@ static int kvm_s390_shadow_tables(struct gmap *sg, unsigned long saddr, 
	ptr = asce.origin * 4096;

	if (asce.r) {

		*fake = 1;

		ptr = 0;

		asce.dt = ASCE_TYPE_REGION1;

	}

	switch (asce.dt) {

	case ASCE_TYPE_REGION1:

		if (vaddr.rfx01 > asce.tl && !asce.r)

		if (vaddr.rfx01 > asce.tl && !*fake)

			return PGM_REGION_FIRST_TRANS;

		break;

	case ASCE_TYPE_REGION2:
@@ -1009,8 +1010,7 @@ static int kvm_s390_shadow_tables(struct gmap *sg, unsigned long saddr, 
		union region1_table_entry rfte;



		if (*fake) {

			/* offset in 16EB guest memory block */

			ptr = ptr + ((unsigned long) vaddr.rsx << 53UL);

			ptr += (unsigned long) vaddr.rfx << 53;

			rfte.val = ptr;

			goto shadow_r2t;

		}
@@ -1036,8 +1036,7 @@ static int kvm_s390_shadow_tables(struct gmap *sg, unsigned long saddr, 
		union region2_table_entry rste;



		if (*fake) {

			/* offset in 8PB guest memory block */

			ptr = ptr + ((unsigned long) vaddr.rtx << 42UL);

			ptr += (unsigned long) vaddr.rsx << 42;

			rste.val = ptr;

			goto shadow_r3t;

		}
@@ -1064,8 +1063,7 @@ static int kvm_s390_shadow_tables(struct gmap *sg, unsigned long saddr, 
		union region3_table_entry rtte;



		if (*fake) {

			/* offset in 4TB guest memory block */

			ptr = ptr + ((unsigned long) vaddr.sx << 31UL);

			ptr += (unsigned long) vaddr.rtx << 31;

			rtte.val = ptr;

			goto shadow_sgt;

		}
@@ -1101,8 +1099,7 @@ static int kvm_s390_shadow_tables(struct gmap *sg, unsigned long saddr, 
		union segment_table_entry ste;



		if (*fake) {

			/* offset in 2G guest memory block */

			ptr = ptr + ((unsigned long) vaddr.sx << 20UL);

			ptr += (unsigned long) vaddr.sx << 20;

			ste.val = ptr;

			goto shadow_pgt;

		}