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Subject[PATCH 5.10 084/530] KVM: s390: VSIE: correctly handle MVPG when in VSIE
Date
From: Claudio Imbrenda <imbrenda@linux.ibm.com>

commit bdf7509bbefa20855d5f6bacdc5b62a8489477c9 upstream.

Correctly handle the MVPG instruction when issued by a VSIE guest.

Fixes: a3508fbe9dc6d ("KVM: s390: vsie: initial support for nested virtualization")
Cc: stable@vger.kernel.org # f85f1baaa189: KVM: s390: split kvm_s390_logical_to_effective
Signed-off-by: Claudio Imbrenda <imbrenda@linux.ibm.com>
Acked-by: Janosch Frank <frankja@linux.ibm.com>
Reviewed-by: David Hildenbrand <david@redhat.com>
Acked-by: Christian Borntraeger <borntraeger@de.ibm.com>
Link: https://lore.kernel.org/r/20210302174443.514363-4-imbrenda@linux.ibm.com
[borntraeger@de.ibm.com: apply fixup from Claudio]
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
arch/s390/kvm/vsie.c | 98 ++++++++++++++++++++++++++++++++++++++++++++++++---
1 file changed, 93 insertions(+), 5 deletions(-)

--- a/arch/s390/kvm/vsie.c
+++ b/arch/s390/kvm/vsie.c
@@ -416,11 +416,6 @@ static void unshadow_scb(struct kvm_vcpu
memcpy((void *)((u64)scb_o + 0xc0),
(void *)((u64)scb_s + 0xc0), 0xf0 - 0xc0);
break;
- case ICPT_PARTEXEC:
- /* MVPG only */
- memcpy((void *)((u64)scb_o + 0xc0),
- (void *)((u64)scb_s + 0xc0), 0xd0 - 0xc0);
- break;
}

if (scb_s->ihcpu != 0xffffU)
@@ -983,6 +978,95 @@ static int handle_stfle(struct kvm_vcpu
}

/*
+ * Get a register for a nested guest.
+ * @vcpu the vcpu of the guest
+ * @vsie_page the vsie_page for the nested guest
+ * @reg the register number, the upper 4 bits are ignored.
+ * returns: the value of the register.
+ */
+static u64 vsie_get_register(struct kvm_vcpu *vcpu, struct vsie_page *vsie_page, u8 reg)
+{
+ /* no need to validate the parameter and/or perform error handling */
+ reg &= 0xf;
+ switch (reg) {
+ case 15:
+ return vsie_page->scb_s.gg15;
+ case 14:
+ return vsie_page->scb_s.gg14;
+ default:
+ return vcpu->run->s.regs.gprs[reg];
+ }
+}
+
+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;
+ u64 *pei_block = &vsie_page->scb_o->mcic;
+ int edat, rc_dest, rc_src;
+ union ctlreg0 cr0;
+
+ 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);
+
+ dest = vsie_get_register(vcpu, vsie_page, scb_s->ipb >> 20) & mask;
+ src = vsie_get_register(vcpu, vsie_page, scb_s->ipb >> 16) & mask;
+
+ 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);
+ /*
+ * Either everything went well, or something non-critical went wrong
+ * e.g. because of a race. In either case, simply retry.
+ */
+ if (rc_dest == -EAGAIN || rc_src == -EAGAIN || (!rc_dest && !rc_src)) {
+ retry_vsie_icpt(vsie_page);
+ return -EAGAIN;
+ }
+ /* Something more serious went wrong, propagate the error */
+ if (rc_dest < 0)
+ return rc_dest;
+ if (rc_src < 0)
+ return rc_src;
+
+ /* The only possible suppressing exception: just deliver it */
+ if (rc_dest == PGM_TRANSLATION_SPEC || rc_src == PGM_TRANSLATION_SPEC) {
+ clear_vsie_icpt(vsie_page);
+ rc_dest = kvm_s390_inject_program_int(vcpu, PGM_TRANSLATION_SPEC);
+ WARN_ON_ONCE(rc_dest);
+ return 1;
+ }
+
+ /*
+ * Forward the PEI intercept to the guest if it was a page fault, or
+ * also for segment and region table faults if EDAT applies.
+ */
+ if (edat) {
+ rc_dest = rc_dest == PGM_ASCE_TYPE ? rc_dest : 0;
+ rc_src = rc_src == PGM_ASCE_TYPE ? rc_src : 0;
+ } else {
+ rc_dest = rc_dest != PGM_PAGE_TRANSLATION ? rc_dest : 0;
+ rc_src = rc_src != PGM_PAGE_TRANSLATION ? rc_src : 0;
+ }
+ if (!rc_dest && !rc_src) {
+ pei_block[0] = pei_dest;
+ pei_block[1] = pei_src;
+ return 1;
+ }
+
+ retry_vsie_icpt(vsie_page);
+
+ /*
+ * The host has edat, and the guest does not, or it was an ASCE type
+ * exception. The host needs to inject the appropriate DAT interrupts
+ * into the guest.
+ */
+ if (rc_dest)
+ return inject_fault(vcpu, rc_dest, dest, 1);
+ return inject_fault(vcpu, rc_src, src, 0);
+}
+
+/*
* Run the vsie on a shadow scb and a shadow gmap, without any further
* sanity checks, handling SIE faults.
*
@@ -1068,6 +1152,10 @@ static int do_vsie_run(struct kvm_vcpu *
if ((scb_s->ipa & 0xf000) != 0xf000)
scb_s->ipa += 0x1000;
break;
+ case ICPT_PARTEXEC:
+ if (scb_s->ipa == 0xb254)
+ rc = vsie_handle_mvpg(vcpu, vsie_page);
+ break;
}
return rc;
}

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