path: root/arch/s390/kvm/vsie.c

/*
 * kvm nested virtualization support for s390x
 *
 * Copyright IBM Corp. 2016
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License (version 2 only)
 * as published by the Free Software Foundation.
 *
 *    Author(s): David Hildenbrand <dahi@linux.vnet.ibm.com>
 */
#include <linux/vmalloc.h>
#include <linux/kvm_host.h>
#include <linux/bug.h>
#include <linux/list.h>
#include <linux/bitmap.h>
#include <asm/gmap.h>
#include <asm/mmu_context.h>
#include <asm/sclp.h>
#include <asm/nmi.h>
#include <asm/dis.h>
#include "kvm-s390.h"
#include "gaccess.h"

struct vsie_page {
	struct kvm_s390_sie_block scb_s;	/* 0x0000 */
	/* the pinned originial scb */
	struct kvm_s390_sie_block *scb_o;	/* 0x0200 */
	/* the shadow gmap in use by the vsie_page */
	struct gmap *gmap;			/* 0x0208 */
	/* address of the last reported fault to guest2 */
	unsigned long fault_addr;		/* 0x0210 */
	__u8 reserved[0x0700 - 0x0218];		/* 0x0218 */
	struct kvm_s390_crypto_cb crycb;	/* 0x0700 */
	__u8 fac[S390_ARCH_FAC_LIST_SIZE_BYTE];	/* 0x0800 */
} __packed;

/* trigger a validity icpt for the given scb */
static int set_validity_icpt(struct kvm_s390_sie_block *scb,
			     __u16 reason_code)
{
	scb->ipa = 0x1000;
	scb->ipb = ((__u32) reason_code) << 16;
	scb->icptcode = ICPT_VALIDITY;
	return 1;
}

/* mark the prefix as unmapped, this will block the VSIE */
static void prefix_unmapped(struct vsie_page *vsie_page)
{
	atomic_or(PROG_REQUEST, &vsie_page->scb_s.prog20);
}

/* mark the prefix as unmapped and wait until the VSIE has been left */
static void prefix_unmapped_sync(struct vsie_page *vsie_page)
{
	prefix_unmapped(vsie_page);
	if (vsie_page->scb_s.prog0c & PROG_IN_SIE)
		atomic_or(CPUSTAT_STOP_INT, &vsie_page->scb_s.cpuflags);
	while (vsie_page->scb_s.prog0c & PROG_IN_SIE)
		cpu_relax();
}

/* mark the prefix as mapped, this will allow the VSIE to run */
static void prefix_mapped(struct vsie_page *vsie_page)
{
	atomic_andnot(PROG_REQUEST, &vsie_page->scb_s.prog20);
}

/* test if the prefix is mapped into the gmap shadow */
static int prefix_is_mapped(struct vsie_page *vsie_page)
{
	return !(atomic_read(&vsie_page->scb_s.prog20) & PROG_REQUEST);
}

/* copy the updated intervention request bits into the shadow scb */
static void update_intervention_requests(struct vsie_page *vsie_page)
{
	const int bits = CPUSTAT_STOP_INT | CPUSTAT_IO_INT | CPUSTAT_EXT_INT;
	int cpuflags;

	cpuflags = atomic_read(&vsie_page->scb_o->cpuflags);
	atomic_andnot(bits, &vsie_page->scb_s.cpuflags);
	atomic_or(cpuflags & bits, &vsie_page->scb_s.cpuflags);
}

/* shadow (filter and validate) the cpuflags  */
static int prepare_cpuflags(struct kvm_vcpu *vcpu, struct vsie_page *vsie_page)
{
	struct kvm_s390_sie_block *scb_s = &vsie_page->scb_s;
	struct kvm_s390_sie_block *scb_o = vsie_page->scb_o;
	int newflags, cpuflags = atomic_read(&scb_o->cpuflags);

	/* we don't allow ESA/390 guests */
	if (!(cpuflags & CPUSTAT_ZARCH))
		return set_validity_icpt(scb_s, 0x0001U);

	if (cpuflags & (CPUSTAT_RRF | CPUSTAT_MCDS))
		return set_validity_icpt(scb_s, 0x0001U);
	else if (cpuflags & (CPUSTAT_SLSV | CPUSTAT_SLSR))
		return set_validity_icpt(scb_s, 0x0007U);

	/* intervention requests will be set later */
	newflags = CPUSTAT_ZARCH;
	if (cpuflags & CPUSTAT_GED && test_kvm_facility(vcpu->kvm, 8))
		newflags |= CPUSTAT_GED;
	if (cpuflags & CPUSTAT_GED2 && test_kvm_facility(vcpu->kvm, 78)) {
		if (cpuflags & CPUSTAT_GED)
			return set_validity_icpt(scb_s, 0x0001U);
		newflags |= CPUSTAT_GED2;
	}
	if (test_kvm_cpu_feat(vcpu->kvm, KVM_S390_VM_CPU_FEAT_GPERE))
		newflags |= cpuflags & CPUSTAT_P;
	if (test_kvm_cpu_feat(vcpu->kvm, KVM_S390_VM_CPU_FEAT_GSLS))
		newflags |= cpuflags & CPUSTAT_SM;
	if (test_kvm_cpu_feat(vcpu->kvm, KVM_S390_VM_CPU_FEAT_IBS))
		newflags |= cpuflags & CPUSTAT_IBS;

	atomic_set(&scb_s->cpuflags, newflags);
	return 0;
}

/*
 * Create a shadow copy of the crycb block and setup key wrapping, if
 * requested for guest 3 and enabled for guest 2.
 *
 * We only accept format-1 (no AP in g2), but convert it into format-2
 * There is nothing to do for format-0.
 *
 * Returns: - 0 if shadowed or nothing to do
 *          - > 0 if control has to be given to guest 2
 */
static int shadow_crycb(struct kvm_vcpu *vcpu, struct vsie_page *vsie_page)
{
	struct kvm_s390_sie_block *scb_s = &vsie_page->scb_s;
	struct kvm_s390_sie_block *scb_o = vsie_page->scb_o;
	u32 crycb_addr = scb_o->crycbd & 0x7ffffff8U;
	unsigned