arch/s390/kvm/diag.c - maze/linux - Git at Google

 /*
  * handling diagnose instructions
  *
  * Copyright IBM Corp. 2008, 2011
  *
  * 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): Carsten Otte <cotte@de.ibm.com>
  *               Christian Borntraeger <borntraeger@de.ibm.com>
  */

 #include <linux/kvm.h>
 #include <linux/kvm_host.h>
 #include <asm/pgalloc.h>
 #include <asm/virtio-ccw.h>
 #include "kvm-s390.h"
 #include "trace.h"
 #include "trace-s390.h"
 #include "gaccess.h"

 static int diag_release_pages(struct kvm_vcpu *vcpu)
 {
 	unsigned long start, end;
 	unsigned long prefix  = vcpu->arch.sie_block->prefix;

 	start = vcpu->run->s.regs.gprs[(vcpu->arch.sie_block->ipa & 0xf0) >> 4];
 	end = vcpu->run->s.regs.gprs[vcpu->arch.sie_block->ipa & 0xf] + 4096;

 	if (start & ~PAGE_MASK || end & ~PAGE_MASK || start > end
 	    || start < 2 * PAGE_SIZE)
 		return kvm_s390_inject_program_int(vcpu, PGM_SPECIFICATION);

 	VCPU_EVENT(vcpu, 5, "diag release pages %lX %lX", start, end);
 	vcpu->stat.diagnose_10++;

 	/* we checked for start > end above */
 	if (end < prefix || start >= prefix + 2 * PAGE_SIZE) {
 		gmap_discard(start, end, vcpu->arch.gmap);
 	} else {
 		if (start < prefix)
 			gmap_discard(start, prefix, vcpu->arch.gmap);
 		if (end >= prefix)
 			gmap_discard(prefix + 2 * PAGE_SIZE,
 				     end, vcpu->arch.gmap);
 	}
 	return 0;
 }

 static int __diag_page_ref_service(struct kvm_vcpu *vcpu)
 {
 	struct prs_parm {
 		u16 code;
 		u16 subcode;
 		u16 parm_len;
 		u16 parm_version;
 		u64 token_addr;
 		u64 select_mask;
 		u64 compare_mask;
 		u64 zarch;
 	};
 	struct prs_parm parm;
 	int rc;
 	u16 rx = (vcpu->arch.sie_block->ipa & 0xf0) >> 4;
 	u16 ry = (vcpu->arch.sie_block->ipa & 0x0f);
 	unsigned long hva_token = KVM_HVA_ERR_BAD;

 	if (vcpu->run->s.regs.gprs[rx] & 7)
 		return kvm_s390_inject_program_int(vcpu, PGM_SPECIFICATION);
 	if (copy_from_guest(vcpu, &parm, vcpu->run->s.regs.gprs[rx], sizeof(parm)))
 		return kvm_s390_inject_program_int(vcpu, PGM_ADDRESSING);
 	if (parm.parm_version != 2 || parm.parm_len < 5 || parm.code != 0x258)
 		return kvm_s390_inject_program_int(vcpu, PGM_SPECIFICATION);

 	switch (parm.subcode) {
 	case 0: /* TOKEN */
 		if (vcpu->arch.pfault_token != KVM_S390_PFAULT_TOKEN_INVALID) {
 			/*
 			 * If the pagefault handshake is already activated,
 			 * the token must not be changed.  We have to return
 			 * decimal 8 instead, as mandated in SC24-6084.
 			 */
 			vcpu->run->s.regs.gprs[ry] = 8;
 			return 0;
 		}

 		if ((parm.compare_mask & parm.select_mask) != parm.compare_mask ||
 		    parm.token_addr & 7 || parm.zarch != 0x8000000000000000ULL)
 			return kvm_s390_inject_program_int(vcpu, PGM_SPECIFICATION);

 		hva_token = gfn_to_hva(vcpu->kvm, gpa_to_gfn(parm.token_addr));
 		if (kvm_is_error_hva(hva_token))
 			return kvm_s390_inject_program_int(vcpu, PGM_ADDRESSING);

 		vcpu->arch.pfault_token = parm.token_addr;
 		vcpu->arch.pfault_select = parm.select_mask;
 		vcpu->arch.pfault_compare = parm.compare_mask;
 		vcpu->run->s.regs.gprs[ry] = 0;
 		rc = 0;
 		break;
 	case 1: /*
 		 * CANCEL
 		 * Specification allows to let already pending tokens survive
 		 * the cancel, therefore to reduce code complexity, we assume
 		 * all outstanding tokens are already pending.
 		 */
 		if (parm.token_addr || parm.select_mask ||
 		    parm.compare_mask || parm.zarch)
 			return kvm_s390_inject_program_int(vcpu, PGM_SPECIFICATION);

 		vcpu->run->s.regs.gprs[ry] = 0;
 		/*
 		 * If the pfault handling was not established or is already
 		 * canceled SC24-6084 requests to return decimal 4.
 		 */
 		if (vcpu->arch.pfault_token == KVM_S390_PFAULT_TOKEN_INVALID)
 			vcpu->run->s.regs.gprs[ry] = 4;
 		else
 			vcpu->arch.pfault_token = KVM_S390_PFAULT_TOKEN_INVALID;

 		rc = 0;
 		break;
 	default:
 		rc = -EOPNOTSUPP;
 		break;
 	}

 	return rc;
 }

 static int __diag_time_slice_end(struct kvm_vcpu *vcpu)
 {
 	VCPU_EVENT(vcpu, 5, "%s", "diag time slice end");
 	vcpu->stat.diagnose_44++;
 	kvm_vcpu_on_spin(vcpu);
 	return 0;
 }

 static int __diag_time_slice_end_directed(struct kvm_vcpu *vcpu)
 {
 	struct kvm *kvm = vcpu->kvm;
 	struct kvm_vcpu *tcpu;
 	int tid;
 	int i;

 	tid = vcpu->run->s.regs.gprs[(vcpu->arch.sie_block->ipa & 0xf0) >> 4];
 	vcpu->stat.diagnose_9c++;
 	VCPU_EVENT(vcpu, 5, "diag time slice end directed to %d", tid);

 	if (tid == vcpu->vcpu_id)
 		return 0;

 	kvm_for_each_vcpu(i, tcpu, kvm)
 		if (tcpu->vcpu_id == tid) {
 			kvm_vcpu_yield_to(tcpu);
 			break;
 		}

 	return 0;
 }

 static int __diag_ipl_functions(struct kvm_vcpu *vcpu)
 {
 	unsigned int reg = vcpu->arch.sie_block->ipa & 0xf;
 	unsigned long subcode = vcpu->run->s.regs.gprs[reg] & 0xffff;

 	VCPU_EVENT(vcpu, 5, "diag ipl functions, subcode %lx", subcode);
 	switch (subcode) {
 	case 3:
 		vcpu->run->s390_reset_flags = KVM_S390_RESET_CLEAR;
 		page_table_reset_pgste(current->mm, 0, TASK_SIZE);
 		break;
 	case 4:
 		vcpu->run->s390_reset_flags = 0;
 		page_table_reset_pgste(current->mm, 0, TASK_SIZE);
 		break;
 	default:
 		return -EOPNOTSUPP;
 	}

 	atomic_set_mask(CPUSTAT_STOPPED, &vcpu->arch.sie_block->cpuflags);
 	vcpu->run->s390_reset_flags |= KVM_S390_RESET_SUBSYSTEM;
 	vcpu->run->s390_reset_flags |= KVM_S390_RESET_IPL;
 	vcpu->run->s390_reset_flags |= KVM_S390_RESET_CPU_INIT;
 	vcpu->run->exit_reason = KVM_EXIT_S390_RESET;
 	VCPU_EVENT(vcpu, 3, "requesting userspace resets %llx",
 	  vcpu->run->s390_reset_flags);
 	trace_kvm_s390_request_resets(vcpu->run->s390_reset_flags);
 	return -EREMOTE;
 }

 static int __diag_virtio_hypercall(struct kvm_vcpu *vcpu)
 {
 	int ret;

 	/* No virtio-ccw notification? Get out quickly. */
 	if (!vcpu->kvm->arch.css_support ||
 	    (vcpu->run->s.regs.gprs[1] != KVM_S390_VIRTIO_CCW_NOTIFY))
 		return -EOPNOTSUPP;

 	/*
 	 * The layout is as follows:
 	 * - gpr 2 contains the subchannel id (passed as addr)
 	 * - gpr 3 contains the virtqueue index (passed as datamatch)
 	 * - gpr 4 contains the index on the bus (optionally)
 	 */
 	ret = kvm_io_bus_write_cookie(vcpu->kvm, KVM_VIRTIO_CCW_NOTIFY_BUS,
 				      vcpu->run->s.regs.gprs[2] & 0xffffffff,
 				      8, &vcpu->run->s.regs.gprs[3],
 				      vcpu->run->s.regs.gprs[4]);

 	/*
 	 * Return cookie in gpr 2, but don't overwrite the register if the
 	 * diagnose will be handled by userspace.
 	 */
 	if (ret != -EOPNOTSUPP)
 		vcpu->run->s.regs.gprs[2] = ret;
 	/* kvm_io_bus_write_cookie returns -EOPNOTSUPP if it found no match. */
 	return ret < 0 ? ret : 0;
 }

 int kvm_s390_handle_diag(struct kvm_vcpu *vcpu)
 {
 	int code = kvm_s390_get_base_disp_rs(vcpu) & 0xffff;

 	if (vcpu->arch.sie_block->gpsw.mask & PSW_MASK_PSTATE)
 		return kvm_s390_inject_program_int(vcpu, PGM_PRIVILEGED_OP);

 	trace_kvm_s390_handle_diag(vcpu, code);
 	switch (code) {
 	case 0x10:
 		return diag_release_pages(vcpu);
 	case 0x44:
 		return __diag_time_slice_end(vcpu);
 	case 0x9c:
 		return __diag_time_slice_end_directed(vcpu);
 	case 0x258:
 		return __diag_page_ref_service(vcpu);
 	case 0x308:
 		return __diag_ipl_functions(vcpu);
 	case 0x500:
 		return __diag_virtio_hypercall(vcpu);
 	default:
 		return -EOPNOTSUPP;
 	}
 }
	/*
	* handling diagnose instructions
	*
	* Copyright IBM Corp. 2008, 2011
	*
	* 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): Carsten Otte <cotte@de.ibm.com>
	* Christian Borntraeger <borntraeger@de.ibm.com>
	*/

	#include <linux/kvm.h>
	#include <linux/kvm_host.h>
	#include <asm/pgalloc.h>
	#include <asm/virtio-ccw.h>
	#include "kvm-s390.h"
	#include "trace.h"
	#include "trace-s390.h"
	#include "gaccess.h"

	static int diag_release_pages(struct kvm_vcpu *vcpu)
	{
	unsigned long start, end;
	unsigned long prefix = vcpu->arch.sie_block->prefix;

	start = vcpu->run->s.regs.gprs[(vcpu->arch.sie_block->ipa & 0xf0) >> 4];
	end = vcpu->run->s.regs.gprs[vcpu->arch.sie_block->ipa & 0xf] + 4096;

	if (start & ~PAGE_MASK \|\| end & ~PAGE_MASK \|\| start > end
	\|\| start < 2 * PAGE_SIZE)
	return kvm_s390_inject_program_int(vcpu, PGM_SPECIFICATION);

	VCPU_EVENT(vcpu, 5, "diag release pages %lX %lX", start, end);
	vcpu->stat.diagnose_10++;

	/* we checked for start > end above */
	if (end < prefix \|\| start >= prefix + 2 * PAGE_SIZE) {
	gmap_discard(start, end, vcpu->arch.gmap);
	} else {
	if (start < prefix)
	gmap_discard(start, prefix, vcpu->arch.gmap);
	if (end >= prefix)
	gmap_discard(prefix + 2 * PAGE_SIZE,
	end, vcpu->arch.gmap);
	}
	return 0;
	}

	static int __diag_page_ref_service(struct kvm_vcpu *vcpu)
	{
	struct prs_parm {
	u16 code;
	u16 subcode;
	u16 parm_len;
	u16 parm_version;
	u64 token_addr;
	u64 select_mask;
	u64 compare_mask;
	u64 zarch;
	};
	struct prs_parm parm;
	int rc;
	u16 rx = (vcpu->arch.sie_block->ipa & 0xf0) >> 4;
	u16 ry = (vcpu->arch.sie_block->ipa & 0x0f);
	unsigned long hva_token = KVM_HVA_ERR_BAD;

	if (vcpu->run->s.regs.gprs[rx] & 7)
	return kvm_s390_inject_program_int(vcpu, PGM_SPECIFICATION);
	if (copy_from_guest(vcpu, &parm, vcpu->run->s.regs.gprs[rx], sizeof(parm)))
	return kvm_s390_inject_program_int(vcpu, PGM_ADDRESSING);
	if (parm.parm_version != 2 \|\| parm.parm_len < 5 \|\| parm.code != 0x258)
	return kvm_s390_inject_program_int(vcpu, PGM_SPECIFICATION);

	switch (parm.subcode) {
	case 0: /* TOKEN */
	if (vcpu->arch.pfault_token != KVM_S390_PFAULT_TOKEN_INVALID) {
	/*
	* If the pagefault handshake is already activated,
	* the token must not be changed. We have to return
	* decimal 8 instead, as mandated in SC24-6084.
	*/
	vcpu->run->s.regs.gprs[ry] = 8;
	return 0;
	}

	if ((parm.compare_mask & parm.select_mask) != parm.compare_mask \|\|
	parm.token_addr & 7 \|\| parm.zarch != 0x8000000000000000ULL)
	return kvm_s390_inject_program_int(vcpu, PGM_SPECIFICATION);

	hva_token = gfn_to_hva(vcpu->kvm, gpa_to_gfn(parm.token_addr));
	if (kvm_is_error_hva(hva_token))
	return kvm_s390_inject_program_int(vcpu, PGM_ADDRESSING);

	vcpu->arch.pfault_token = parm.token_addr;
	vcpu->arch.pfault_select = parm.select_mask;
	vcpu->arch.pfault_compare = parm.compare_mask;
	vcpu->run->s.regs.gprs[ry] = 0;
	rc = 0;
	break;
	case 1: /*
	* CANCEL
	* Specification allows to let already pending tokens survive
	* the cancel, therefore to reduce code complexity, we assume
	* all outstanding tokens are already pending.
	*/
	if (parm.token_addr \|\| parm.select_mask \|\|
	parm.compare_mask \|\| parm.zarch)
	return kvm_s390_inject_program_int(vcpu, PGM_SPECIFICATION);

	vcpu->run->s.regs.gprs[ry] = 0;
	/*
	* If the pfault handling was not established or is already
	* canceled SC24-6084 requests to return decimal 4.
	*/
	if (vcpu->arch.pfault_token == KVM_S390_PFAULT_TOKEN_INVALID)
	vcpu->run->s.regs.gprs[ry] = 4;
	else
	vcpu->arch.pfault_token = KVM_S390_PFAULT_TOKEN_INVALID;

	rc = 0;
	break;
	default:
	rc = -EOPNOTSUPP;
	break;
	}

	return rc;
	}

	static int __diag_time_slice_end(struct kvm_vcpu *vcpu)
	{
	VCPU_EVENT(vcpu, 5, "%s", "diag time slice end");
	vcpu->stat.diagnose_44++;
	kvm_vcpu_on_spin(vcpu);
	return 0;
	}

	static int __diag_time_slice_end_directed(struct kvm_vcpu *vcpu)
	{
	struct kvm *kvm = vcpu->kvm;
	struct kvm_vcpu *tcpu;
	int tid;
	int i;

	tid = vcpu->run->s.regs.gprs[(vcpu->arch.sie_block->ipa & 0xf0) >> 4];
	vcpu->stat.diagnose_9c++;
	VCPU_EVENT(vcpu, 5, "diag time slice end directed to %d", tid);

	if (tid == vcpu->vcpu_id)
	return 0;

	kvm_for_each_vcpu(i, tcpu, kvm)
	if (tcpu->vcpu_id == tid) {
	kvm_vcpu_yield_to(tcpu);
	break;
	}

	return 0;
	}

	static int __diag_ipl_functions(struct kvm_vcpu *vcpu)
	{
	unsigned int reg = vcpu->arch.sie_block->ipa & 0xf;
	unsigned long subcode = vcpu->run->s.regs.gprs[reg] & 0xffff;

	VCPU_EVENT(vcpu, 5, "diag ipl functions, subcode %lx", subcode);
	switch (subcode) {
	case 3:
	vcpu->run->s390_reset_flags = KVM_S390_RESET_CLEAR;
	page_table_reset_pgste(current->mm, 0, TASK_SIZE);
	break;
	case 4:
	vcpu->run->s390_reset_flags = 0;
	page_table_reset_pgste(current->mm, 0, TASK_SIZE);
	break;
	default:
	return -EOPNOTSUPP;
	}

	atomic_set_mask(CPUSTAT_STOPPED, &vcpu->arch.sie_block->cpuflags);
	vcpu->run->s390_reset_flags \|= KVM_S390_RESET_SUBSYSTEM;
	vcpu->run->s390_reset_flags \|= KVM_S390_RESET_IPL;
	vcpu->run->s390_reset_flags \|= KVM_S390_RESET_CPU_INIT;
	vcpu->run->exit_reason = KVM_EXIT_S390_RESET;
	VCPU_EVENT(vcpu, 3, "requesting userspace resets %llx",
	vcpu->run->s390_reset_flags);
	trace_kvm_s390_request_resets(vcpu->run->s390_reset_flags);
	return -EREMOTE;
	}

	static int __diag_virtio_hypercall(struct kvm_vcpu *vcpu)
	{
	int ret;

	/* No virtio-ccw notification? Get out quickly. */
	if (!vcpu->kvm->arch.css_support \|\|
	(vcpu->run->s.regs.gprs[1] != KVM_S390_VIRTIO_CCW_NOTIFY))
	return -EOPNOTSUPP;

	/*
	* The layout is as follows:
	* - gpr 2 contains the subchannel id (passed as addr)
	* - gpr 3 contains the virtqueue index (passed as datamatch)
	* - gpr 4 contains the index on the bus (optionally)
	*/
	ret = kvm_io_bus_write_cookie(vcpu->kvm, KVM_VIRTIO_CCW_NOTIFY_BUS,
	vcpu->run->s.regs.gprs[2] & 0xffffffff,
	8, &vcpu->run->s.regs.gprs[3],
	vcpu->run->s.regs.gprs[4]);

	/*
	* Return cookie in gpr 2, but don't overwrite the register if the
	* diagnose will be handled by userspace.
	*/
	if (ret != -EOPNOTSUPP)
	vcpu->run->s.regs.gprs[2] = ret;
	/* kvm_io_bus_write_cookie returns -EOPNOTSUPP if it found no match. */
	return ret < 0 ? ret : 0;
	}

	int kvm_s390_handle_diag(struct kvm_vcpu *vcpu)
	{
	int code = kvm_s390_get_base_disp_rs(vcpu) & 0xffff;

	if (vcpu->arch.sie_block->gpsw.mask & PSW_MASK_PSTATE)
	return kvm_s390_inject_program_int(vcpu, PGM_PRIVILEGED_OP);

	trace_kvm_s390_handle_diag(vcpu, code);
	switch (code) {
	case 0x10:
	return diag_release_pages(vcpu);
	case 0x44:
	return __diag_time_slice_end(vcpu);
	case 0x9c:
	return __diag_time_slice_end_directed(vcpu);
	case 0x258:
	return __diag_page_ref_service(vcpu);
	case 0x308:
	return __diag_ipl_functions(vcpu);
	case 0x500:
	return __diag_virtio_hypercall(vcpu);
	default:
	return -EOPNOTSUPP;
	}
	}