1 files changed, 263 insertions, 0 deletions
diff --git a/arch/s390/kvm/diag.c b/arch/s390/kvm/diag.c
new file mode 100644
index 000000000..45634b3d2
--- /dev/null
+++ b/arch/s390/kvm/diag.c
@@ -0,0 +1,263 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * handling diagnose instructions
+ *
+ * Copyright IBM Corp. 2008, 2011
+ *
+ *    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/gmap.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  = kvm_s390_get_prefix(vcpu);
+
+	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] + PAGE_SIZE;
+	vcpu->stat.diagnose_10++;
+
+	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);
+
+	/*
+	 * We checked for start >= end above, so lets check for the
+	 * fast path (no prefix swap page involved)
+	 */
+	if (end <= prefix || start >= prefix + 2 * PAGE_SIZE) {
+		gmap_discard(vcpu->arch.gmap, start, end);
+	} else {
+		/*
+		 * This is slow path.  gmap_discard will check for start
+		 * so lets split this into before prefix, prefix, after
+		 * prefix and let gmap_discard make some of these calls
+		 * NOPs.
+		 */
+		gmap_discard(vcpu->arch.gmap, start, prefix);
+		if (start <= prefix)
+			gmap_discard(vcpu->arch.gmap, 0, PAGE_SIZE);
+		if (end > prefix + PAGE_SIZE)
+			gmap_discard(vcpu->arch.gmap, PAGE_SIZE, 2 * PAGE_SIZE);
+		gmap_discard(vcpu->arch.gmap, prefix + 2 * PAGE_SIZE, end);
+	}
+	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);
+
+	VCPU_EVENT(vcpu, 3, "diag page reference parameter block at 0x%llx",
+		   vcpu->run->s.regs.gprs[rx]);
+	vcpu->stat.diagnose_258++;
+	if (vcpu->run->s.regs.gprs[rx] & 7)
+		return kvm_s390_inject_program_int(vcpu, PGM_SPECIFICATION);
+	rc = read_guest(vcpu, vcpu->run->s.regs.gprs[rx], rx, &parm, sizeof(parm));
+	if (rc)
+		return kvm_s390_inject_prog_cond(vcpu, rc);
+	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 */
+		VCPU_EVENT(vcpu, 3, "pageref token addr 0x%llx "
+			   "select mask 0x%llx compare mask 0x%llx",
+			   parm.token_addr, parm.select_mask, parm.compare_mask);
+		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);
+
+		if (kvm_is_error_gpa(vcpu->kvm, parm.token_addr))
+			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.
+		 */
+		VCPU_EVENT(vcpu, 3, "pageref cancel addr 0x%llx", parm.token_addr);
+		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, true);
+	return 0;
+}
+
+static int __diag_time_slice_end_directed(struct kvm_vcpu *vcpu)
+{
+	struct kvm_vcpu *tcpu;
+	int tid;
+
+	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;
+
+	tcpu = kvm_get_vcpu_by_id(vcpu->kvm, tid);
+	if (tcpu)
+		kvm_vcpu_yield_to(tcpu);
+	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, 3, "diag ipl functions, subcode %lx", subcode);
+	vcpu->stat.diagnose_308++;
+	switch (subcode) {
+	case 3:
+		vcpu->run->s390_reset_flags = KVM_S390_RESET_CLEAR;
+		break;
+	case 4:
+		vcpu->run->s390_reset_flags = 0;
+		break;
+	default:
+		return -EOPNOTSUPP;
+	}
+
+	if (!kvm_s390_user_cpu_state_ctrl(vcpu->kvm))
+		kvm_s390_vcpu_stop(vcpu);
+	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;
+
+	vcpu->stat.diagnose_500++;
+	/* 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;
+
+	VCPU_EVENT(vcpu, 4, "diag 0x500 schid 0x%8.8x queue 0x%x cookie 0x%llx",
+			    (u32) vcpu->run->s.regs.gprs[2],
+			    (u32) vcpu->run->s.regs.gprs[3],
+			    vcpu->run->s.regs.gprs[4]);
+
+	/*
+	 * 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_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, NULL) & 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:
+		vcpu->stat.diagnose_other++;
+		return -EOPNOTSUPP;
+	}
+}