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

// SPDX-License-Identifier: GPL-2.0
/*
 * kvm nested virtualization support for s390x
 *
 * Copyright IBM Corp. 2016, 2018
 *
 *    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 <linux/sched/signal.h>
#include <linux/io.h>

#include <asm/gmap.h>
#include <asm/mmu_context.h>
#include <asm/sclp.h>
#include <asm/nmi.h>
#include <asm/dis.h>
#include <asm/facility.h>
#include "kvm-s390.h"
#include "gaccess.h"

struct vsie_page {
	struct kvm_s390_sie_block scb_s;	/* 0x0000 */
	/*
	 * the backup info for machine check. ensure it's at
	 * the same offset as that in struct sie_page!
	 */
	struct mcck_volatile_info mcck_info;    /* 0x0200 */
	/*
	 * The pinned original scb. Be aware that other VCPUs can modify
	 * it while we read from it. Values that are used for conditions or
	 * are reused conditionally, should be accessed via READ_ONCE.
	 */
	struct kvm_s390_sie_block *scb_o;	/* 0x0218 */
	/* the shadow gmap in use by the vsie_page */
	struct gmap *gmap;			/* 0x0220 */
	/* address of the last reported fault to guest2 */
	unsigned long fault_addr;		/* 0x0228 */
	/* calculated guest addresses of satellite control blocks */
	gpa_t sca_gpa;				/* 0x0230 */
	gpa_t itdba_gpa;			/* 0x0238 */
	gpa_t gvrd_gpa;				/* 0x0240 */
	gpa_t riccbd_gpa;			/* 0x0248 */
	gpa_t sdnx_gpa;				/* 0x0250 */
	__u8 reserved[0x0700 - 0x0258];		/* 0x0258 */
	struct kvm_s390_crypto_cb crycb;	/* 0x0700 */
	__u8 fac[S390_ARCH_FAC_LIST_SIZE_BYTE];	/* 0x0800 */
};

/* 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;
	if (test_kvm_cpu_feat(vcpu->kvm, KVM_S390_VM_CPU_FEAT_KSS))
		newflags |= cpuflags & CPUSTAT_KSS;

	atomic_set(&scb_s->cpuflags, newflags);
	return 0;
}
/* Copy to APCB FORMAT1 from APCB FORMAT0 */
static int setup_apcb10(struct kvm_vcpu *vcpu, struct kvm_s390_apcb1 *apcb_s,
			unsigned long crycb_gpa, struct kvm_s390_apcb1 *apcb_h)
{
	struct kvm_s390_apcb0 tmp;
	unsigned long apcb_gpa;

	apcb_gpa = crycb_gpa + offsetof(struct kvm_s390_crypto_cb, apcb0);

	if (read_guest_real(vcpu, apcb_gpa, &tmp,
			    sizeof(struct kvm_s390_apcb0)))
		return -EFAULT;

	apcb_s->apm[0] = apcb_h->apm[0] & tmp.apm[0];
	apcb_s->aqm[0] = apcb_h->aqm[0] & tmp.aqm[0] & 0xffff000000000000UL;
	apcb_s->adm[0] = apcb_h->adm[0] & tmp.adm[0] & 0xffff000000000000UL;

	return 0;

}

/**
 * setup_apcb00 - Copy to APCB FORMAT0 from APCB FORMAT0
 * @vcpu: pointer to the virtual CPU
 * @apcb_s: pointer to start of apcb in the shadow crycb
 * @crycb_gpa: guest physical address to start of original guest crycb
 * @apcb_h: pointer to start of apcb in the guest1
 *
 * Returns 0 and -EFAULT on error reading guest apcb
 */
static int setup_apcb00(struct kvm_vcpu *vcpu, unsigned long *apcb_s,
			unsigned long crycb_gpa, unsigned long *apcb_h)
{
	unsigned long apcb_gpa;

	apcb_gpa = crycb_gpa + offsetof(struct kvm_s390_crypto_cb, apcb0);

	if (read_guest_real(vcpu, apcb_gpa, apcb_s,
			    sizeof(struct kvm_s390_apcb0)))
		return -EFAULT;

	bitmap_and(apcb_s, apcb_s, apcb_h,
		   BITS_PER_BYTE * sizeof(struct kvm_s390_apcb0));

	return 0;
}

/**
 * setup_apcb11 - Copy the FORMAT1 APCB from the guest to the shadow CRYCB
 * @vcpu: pointer to the virtual CPU
 * @apcb_s: pointer to start of apcb in the shadow crycb
 * @crycb_gpa: guest physical address to start of original guest crycb
 * @apcb_h: pointer to start of apcb in the host
 *
 * Returns 0 and -EFAULT on error reading guest apcb
 */
static int setup_apcb11(struct kvm_vcpu *vcpu, unsigned long *apcb_s,
			unsigned long crycb_gpa,
			unsigned long *apcb_h)
{
	unsigned long apcb_gpa;

	apcb_gpa = crycb_gpa + offsetof(struct kvm_s390_crypto_cb, apcb1);

	if (read_guest_real(vcpu, apcb_gpa, apcb_s,
			    sizeof(struct kvm_s390_apcb1)))
		return -EFAULT;

	bitmap_and(apcb_s, apcb_s, apcb_h,
		   BITS_PER_BYTE * sizeof(struct kvm_s390_apcb1));

	return 0;
}

/**
 * setup_apcb - Create a shadow copy of the apcb.
 * @vcpu: pointer to the virtual CPU
 * @crycb_s: pointer to shadow crycb
 * @crycb_gpa: guest physical address of original guest crycb
 * @crycb_h: pointer to the host crycb
 * @fmt_o: format of the original guest crycb.
 * @fmt_h: format of the host crycb.
 *
 * Checks the compatibility between the guest and host crycb and calls the
 * appropriate copy function.
 *
 * Return 0 or an error number if the guest and host crycb are incompatible.
 */
static int setup_apcb(struct kvm_vcpu *vcpu, struct kvm_s390_crypto_cb *crycb_s,
	       const u32 crycb_gpa,
	       struct kvm_s390_crypto_cb *crycb_h,
	       int fmt_o, int fmt_h)
{
	switch (fmt_o) {
	case CRYCB_FORMAT2:
		if ((crycb_gpa & PAGE_MASK) != ((crycb_gpa + 256) & PAGE_MASK))
			return -EACCES;
		if (fmt_h != CRYCB_FORMAT2)
			return -EINVAL;
		return setup_apcb11(vcpu, (unsigned long *)&crycb_s->apcb1,
				    cr