On 19.03.21 20:33, Claudio Imbrenda wrote:

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@vger.kernel.org Signed-off-by: Claudio Imbrenda imbrenda@linux.ibm.com

---

arch/s390/kvm/vsie.c | 10 +++++++--- 1 file changed, 7 insertions(+), 3 deletions(-)

diff --git a/arch/s390/kvm/vsie.c b/arch/s390/kvm/vsie.c index 48aab6290a77..92864f9b3d84 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, r1, r2, src, dest, 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 = READ_ONCE(vsie_page->scb_o->mso) & ~(1UL << 20);

I think we should use the one stored in the shadow page - this is what the SIE saw and will see when retrying.

• prefix = scb_s->prefix << GUEST_PREFIX_SHIFT;

• dest = vsie_get_register(vcpu, vsie_page, scb_s->ipb >> 16) & mask;
• src = vsie_get_register(vcpu, vsie_page, scb_s->ipb >> 20) & mask;

• r1 = vsie_get_register(vcpu, vsie_page, scb_s->ipb >> 16);
• r2 = vsie_get_register(vcpu, vsie_page, scb_s->ipb >> 20);

Just reuse dest and src here?

• dest = _kvm_s390_real_to_abs(prefix, r1 & mask) + mso;
• src = _kvm_s390_real_to_abs(prefix, r2 & mask) + 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);

Apart from that, looks good to me.