KVM: s390: gs support for kvm guests

This patch adds guarded storage support for KVM guest. We need to
setup the necessary control blocks, the kvm_run structure for the
new registers, the necessary wrappers for VSIE, as well as the
machine check save areas.
GS is enabled lazily and the register saving and reloading is done in
KVM code.  As this feature adds new content for migration, we provide
a new capability for enablement (KVM_CAP_S390_GS).

Signed-off-by: Fan Zhang <zhangfan@linux.vnet.ibm.com>
Reviewed-by: Christian Borntraeger <borntraeger@de.ibm.com>
Reviewed-by: Janosch Frank <frankja@linux.vnet.ibm.com>
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>

1 files changed, 31 insertions, 2 deletions

diff --git a/arch/s390/kvm/interrupt.c b/arch/s390/kvm/interrupt.c
index 169558dc7daf..311eef0df855 100644
--- a/arch/s390/kvm/interrupt.c
+++ b/arch/s390/kvm/interrupt.c
@@ -410,6 +410,7 @@ static int __write_machine_check(struct kvm_vcpu *vcpu,
 				 struct kvm_s390_mchk_info *mchk)
 {
 	unsigned long ext_sa_addr;
+	unsigned long lc;
 	freg_t fprs[NUM_FPRS];
 	union mci mci;
 	int rc;
@@ -422,8 +423,28 @@ static int __write_machine_check(struct kvm_vcpu *vcpu,
 	/* Extended save area */
 	rc = read_guest_lc(vcpu, __LC_MCESAD, &ext_sa_addr,
 			   sizeof(unsigned long));
-	/* Only bits 0-53 are used for address formation */
-	ext_sa_addr &= ~0x3ffUL;
+	/* Only bits 0 through 63-LC are used for address formation */
+	lc = ext_sa_addr & MCESA_LC_MASK;
+	if (test_kvm_facility(vcpu->kvm, 133)) {
+		switch (lc) {
+		case 0:
+		case 10:
+			ext_sa_addr &= ~0x3ffUL;
+			break;
+		case 11:
+			ext_sa_addr &= ~0x7ffUL;
+			break;
+		case 12:
+			ext_sa_addr &= ~0xfffUL;
+			break;
+		default:
+			ext_sa_addr = 0;
+			break;
+		}
+	} else {
+		ext_sa_addr &= ~0x3ffUL;
+	}
+
 	if (!rc && mci.vr && ext_sa_addr && test_kvm_facility(vcpu->kvm, 129)) {
 		if (write_guest_abs(vcpu, ext_sa_addr, vcpu->run->s.regs.vrs,
 				    512))
@@ -431,6 +452,14 @@ static int __write_machine_check(struct kvm_vcpu *vcpu,
 	} else {
 		mci.vr = 0;
 	}
+	if (!rc && mci.gs && ext_sa_addr && test_kvm_facility(vcpu->kvm, 133)
+	    && (lc == 11 || lc == 12)) {
+		if (write_guest_abs(vcpu, ext_sa_addr + 1024,
+				    &vcpu->run->s.regs.gscb, 32))
+			mci.gs = 0;
+	} else {
+		mci.gs = 0;
+	}
 
 	/* General interruption information */
 	rc |= put_guest_lc(vcpu, 1, (u8 __user *) __LC_AR_MODE_ID);