Merge tag 'kvm-s390-next-5.7-1' of git://git.kernel.org/pub/scm/linux/kernel/git/kvms390/linux into HEAD

KVM: s390: Features and Enhancements for 5.7 part1

1. Allow to disable gisa
2. protected virtual machines
  Protected VMs (PVM) are KVM VMs, where KVM can't access the VM's
  state like guest memory and guest registers anymore. Instead the
  PVMs are mostly managed by a new entity called Ultravisor (UV),
  which provides an API, so KVM and the PV can request management
  actions.

  PVMs are encrypted at rest and protected from hypervisor access
  while running.  They switch from a normal operation into protected
  mode, so we can still use the standard boot process to load a
  encrypted blob and then move it into protected mode.

  Rebooting is only possible by passing through the unprotected/normal
  mode and switching to protected again.

  One mm related patch will go via Andrews mm tree ( mm/gup/writeback:
  add callbacks for inaccessible pages)

1 files changed, 116 insertions, 6 deletions

diff --git a/arch/s390/kvm/intercept.c b/arch/s390/kvm/intercept.c
index 3655196f1c03..e7a7c499a73f 100644
--- a/arch/s390/kvm/intercept.c
+++ b/arch/s390/kvm/intercept.c
@@ -2,7 +2,7 @@
 /*
  * in-kernel handling for sie intercepts
  *
- * Copyright IBM Corp. 2008, 2014
+ * Copyright IBM Corp. 2008, 2020
  *
  *    Author(s): Carsten Otte <cotte@de.ibm.com>
  *               Christian Borntraeger <borntraeger@de.ibm.com>
@@ -15,6 +15,7 @@
 #include <asm/asm-offsets.h>
 #include <asm/irq.h>
 #include <asm/sysinfo.h>
+#include <asm/uv.h>
 
 #include "kvm-s390.h"
 #include "gaccess.h"
@@ -78,6 +79,10 @@ static int handle_stop(struct kvm_vcpu *vcpu)
 			return rc;
 	}
 
+	/*
+	 * no need to check the return value of vcpu_stop as it can only have
+	 * an error for protvirt, but protvirt means user cpu state
+	 */
 	if (!kvm_s390_user_cpu_state_ctrl(vcpu->kvm))
 		kvm_s390_vcpu_stop(vcpu);
 	return -EOPNOTSUPP;
@@ -230,6 +235,13 @@ static int handle_prog(struct kvm_vcpu *vcpu)
 
 	vcpu->stat.exit_program_interruption++;
 
+	/*
+	 * Intercept 8 indicates a loop of specification exceptions
+	 * for protected guests.
+	 */
+	if (kvm_s390_pv_cpu_is_protected(vcpu))
+		return -EOPNOTSUPP;
+
 	if (guestdbg_enabled(vcpu) && per_event(vcpu)) {
 		rc = kvm_s390_handle_per_event(vcpu);
 		if (rc)
@@ -383,7 +395,7 @@ int handle_sthyi(struct kvm_vcpu *vcpu)
 		goto out;
 	}
 
-	if (addr & ~PAGE_MASK)
+	if (!kvm_s390_pv_cpu_is_protected(vcpu) && (addr & ~PAGE_MASK))
 		return kvm_s390_inject_program_int(vcpu, PGM_SPECIFICATION);
 
 	sctns = (void *)get_zeroed_page(GFP_KERNEL);
@@ -394,10 +406,15 @@ int handle_sthyi(struct kvm_vcpu *vcpu)
 
 out:
 	if (!cc) {
-		r = write_guest(vcpu, addr, reg2, sctns, PAGE_SIZE);
-		if (r) {
-			free_page((unsigned long)sctns);
-			return kvm_s390_inject_prog_cond(vcpu, r);
+		if (kvm_s390_pv_cpu_is_protected(vcpu)) {
+			memcpy((void *)(sida_origin(vcpu->arch.sie_block)),
+			       sctns, PAGE_SIZE);
+		} else {
+			r = write_guest(vcpu, addr, reg2, sctns, PAGE_SIZE);
+			if (r) {
+				free_page((unsigned long)sctns);
+				return kvm_s390_inject_prog_cond(vcpu, r);
+			}
 		}
 	}
 
@@ -443,6 +460,77 @@ static int handle_operexc(struct kvm_vcpu *vcpu)
 	return kvm_s390_inject_program_int(vcpu, PGM_OPERATION);
 }
 
+static int handle_pv_spx(struct kvm_vcpu *vcpu)
+{
+	u32 pref = *(u32 *)vcpu->arch.sie_block->sidad;
+
+	kvm_s390_set_prefix(vcpu, pref);
+	trace_kvm_s390_handle_prefix(vcpu, 1, pref);
+	return 0;
+}
+
+static int handle_pv_sclp(struct kvm_vcpu *vcpu)
+{
+	struct kvm_s390_float_interrupt *fi = &vcpu->kvm->arch.float_int;
+
+	spin_lock(&fi->lock);
+	/*
+	 * 2 cases:
+	 * a: an sccb answering interrupt was already pending or in flight.
+	 *    As the sccb value is not known we can simply set some value to
+	 *    trigger delivery of a saved SCCB. UV will then use its saved
+	 *    copy of the SCCB value.
+	 * b: an error SCCB interrupt needs to be injected so we also inject
+	 *    a fake SCCB address. Firmware will use the proper one.
+	 * This makes sure, that both errors and real sccb returns will only
+	 * be delivered after a notification intercept (instruction has
+	 * finished) but not after others.
+	 */
+	fi->srv_signal.ext_params |= 0x43000;
+	set_bit(IRQ_PEND_EXT_SERVICE, &fi->pending_irqs);
+	clear_bit(IRQ_PEND_EXT_SERVICE, &fi->masked_irqs);
+	spin_unlock(&fi->lock);
+	return 0;
+}
+
+static int handle_pv_uvc(struct kvm_vcpu *vcpu)
+{
+	struct uv_cb_share *guest_uvcb = (void *)vcpu->arch.sie_block->sidad;
+	struct uv_cb_cts uvcb = {
+		.header.cmd	= UVC_CMD_UNPIN_PAGE_SHARED,
+		.header.len	= sizeof(uvcb),
+		.guest_handle	= kvm_s390_pv_get_handle(vcpu->kvm),
+		.gaddr		= guest_uvcb->paddr,
+	};
+	int rc;
+
+	if (guest_uvcb->header.cmd != UVC_CMD_REMOVE_SHARED_ACCESS) {
+		WARN_ONCE(1, "Unexpected notification intercept for UVC 0x%x\n",
+			  guest_uvcb->header.cmd);
+		return 0;
+	}
+	rc = gmap_make_secure(vcpu->arch.gmap, uvcb.gaddr, &uvcb);
+	/*
+	 * If the unpin did not succeed, the guest will exit again for the UVC
+	 * and we will retry the unpin.
+	 */
+	if (rc == -EINVAL)
+		return 0;
+	return rc;
+}
+
+static int handle_pv_notification(struct kvm_vcpu *vcpu)
+{
+	if (vcpu->arch.sie_block->ipa == 0xb210)
+		return handle_pv_spx(vcpu);
+	if (vcpu->arch.sie_block->ipa == 0xb220)
+		return handle_pv_sclp(vcpu);
+	if (vcpu->arch.sie_block->ipa == 0xb9a4)
+		return handle_pv_uvc(vcpu);
+
+	return handle_instruction(vcpu);
+}
+
 int kvm_handle_sie_intercept(struct kvm_vcpu *vcpu)
 {
 	int rc, per_rc = 0;
@@ -479,6 +567,28 @@ int kvm_handle_sie_intercept(struct kvm_vcpu *vcpu)
 	case ICPT_KSS:
 		rc = kvm_s390_skey_check_enable(vcpu);
 		break;
+	case ICPT_MCHKREQ:
+	case ICPT_INT_ENABLE:
+		/*
+		 * PSW bit 13 or a CR (0, 6, 14) changed and we might
+		 * now be able to deliver interrupts. The pre-run code
+		 * will take care of this.
+		 */
+		rc = 0;
+		break;
+	case ICPT_PV_INSTR:
+		rc = handle_instruction(vcpu);
+		break;
+	case ICPT_PV_NOTIFY:
+		rc = handle_pv_notification(vcpu);
+		break;
+	case ICPT_PV_PREF:
+		rc = 0;
+		gmap_convert_to_secure(vcpu->arch.gmap,
+				       kvm_s390_get_prefix(vcpu));
+		gmap_convert_to_secure(vcpu->arch.gmap,
+				       kvm_s390_get_prefix(vcpu) + PAGE_SIZE);
+		break;
 	default:
 		return -EOPNOTSUPP;
 	}