linux-kernel - [PATCH v2 2/2] s390/kvm: VSIE: fix MVPG handling for prefixing and MSO

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Message-Id: <20210322140559.500716-3-imbrenda@linux.ibm.com>
Date:   Mon, 22 Mar 2021 15:05:59 +0100
From:   Claudio Imbrenda <imbrenda@...ux.ibm.com>
To:     linux-kernel@...r.kernel.org
Cc:     borntraeger@...ibm.com, frankja@...ux.ibm.com, david@...hat.com,
        cohuck@...hat.com, kvm@...r.kernel.org, linux-s390@...r.kernel.org,
        stable@...r.kernel.org
Subject: [PATCH v2 2/2] s390/kvm: VSIE: fix MVPG handling for prefixing and MSO

Prefixing needs to be applied to the guest real address to translate it
into a guest absolute address.

The value of MSO needs to be added to a guest-absolute address in order to
obtain the host-virtual.

Fixes: 223ea46de9e79 ("s390/kvm: VSIE: correctly handle MVPG when in VSIE")
Cc: stable@...r.kernel.org
Signed-off-by: Claudio Imbrenda <imbrenda@...ux.ibm.com>
Reported-by: Janosch Frank <frankja@...ux.ibm.com>
---
 arch/s390/kvm/vsie.c | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/arch/s390/kvm/vsie.c b/arch/s390/kvm/vsie.c
index 48aab6290a77..ac86f11e46dc 100644
--- a/arch/s390/kvm/vsie.c
+++ b/arch/s390/kvm/vsie.c
@@ -1002,7 +1002,7 @@ static u64 vsie_get_register(struct kvm_vcpu *vcpu, struct vsie_page *vsie_page,
 static int vsie_handle_mvpg(struct kvm_vcpu *vcpu, struct vsie_page *vsie_page)
 {
 	struct kvm_s390_sie_block *scb_s = &vsie_page->scb_s;
-	unsigned long pei_dest, pei_src, src, dest, mask;
+	unsigned long pei_dest, pei_src, dest, src, mask, mso, prefix;
 	u64 *pei_block = &vsie_page->scb_o->mcic;
 	int edat, rc_dest, rc_src;
 	union ctlreg0 cr0;
@@ -1010,9 +1010,13 @@ static int vsie_handle_mvpg(struct kvm_vcpu *vcpu, struct vsie_page *vsie_page)
 	cr0.val = vcpu->arch.sie_block->gcr[0];
 	edat = cr0.edat && test_kvm_facility(vcpu->kvm, 8);
 	mask = _kvm_s390_logical_to_effective(&scb_s->gpsw, PAGE_MASK);
+	mso = scb_s->mso & ~(1UL << 20);
+	prefix = scb_s->prefix << GUEST_PREFIX_SHIFT;
 
 	dest = vsie_get_register(vcpu, vsie_page, scb_s->ipb >> 16) & mask;
+	dest = _kvm_s390_real_to_abs(prefix, dest) + mso;
 	src = vsie_get_register(vcpu, vsie_page, scb_s->ipb >> 20) & mask;
+	src = _kvm_s390_real_to_abs(prefix, src) + mso;
 
 	rc_dest = kvm_s390_shadow_fault(vcpu, vsie_page->gmap, dest, &pei_dest);
 	rc_src = kvm_s390_shadow_fault(vcpu, vsie_page->gmap, src, &pei_src);
-- 
2.26.2