[PATCH v1 2/2] s390/kvm: VSIE: fix MVPG handling for prefixing and MSO

Claudio Imbrenda
2021-03-19T19:34:48Z

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);
+ 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);
+ 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);
--
2.26.2