Commit bdf7509b authored by Claudio Imbrenda's avatar Claudio Imbrenda Committed by Christian Borntraeger
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KVM: s390: VSIE: correctly handle MVPG when in VSIE 



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

Fixes: a3508fbe ("KVM: s390: vsie: initial support for nested virtualization")
Cc: stable@vger.kernel.org # f85f1baa: KVM: s390: split kvm_s390_logical_to_effective
Signed-off-by: default avatarClaudio Imbrenda <imbrenda@linux.ibm.com>
Acked-by: default avatarJanosch Frank <frankja@linux.ibm.com>
Reviewed-by: default avatarDavid Hildenbrand <david@redhat.com>
Acked-by: default avatarChristian 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: default avatarChristian Borntraeger <borntraeger@de.ibm.com>
parent 5ac14bac

arch/s390/kvm/vsie.c

+93 −5
Original line number Diff line number Diff line
@@ -417,11 +417,6 @@ static void unshadow_scb(struct kvm_vcpu *vcpu, struct vsie_page *vsie_page) 
		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 *vcpu, struct vsie_page *vsie_page) 
	return 0;

}



/*

 * 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.
@@ -1071,6 +1155,10 @@ static int do_vsie_run(struct kvm_vcpu *vcpu, struct vsie_page *vsie_page) 
		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;

}