KVM: s390: intercepts for privileged instructions

This patch introduces in-kernel handling of some intercepts for privileged
instructions:

handle_set_prefix()        sets the prefix register of the local cpu
handle_store_prefix()      stores the content of the prefix register to memory
handle_store_cpu_address() stores the cpu number of the current cpu to memory
handle_skey()              just decrements the instruction address and retries
handle_stsch()             delivers condition code 3 "operation not supported"
handle_chsc()              same here
handle_stfl()              stores the facility list which contains the
                           capabilities of the cpu
handle_stidp()             stores cpu type/model/revision and such
handle_stsi()              stores information about the system topology

Acked-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Carsten Otte <cotte@de.ibm.com>
Signed-off-by: Avi Kivity <avi@qumranet.com>

1 files changed, 323 insertions, 0 deletions

diff --git a/arch/s390/kvm/priv.c b/arch/s390/kvm/priv.c
new file mode 100644
index 000000000000..c97e904ca3b3
--- /dev/null
+++ b/arch/s390/kvm/priv.c
@@ -0,0 +1,323 @@
+/*
+ * priv.c - handling privileged instructions
+ *
+ * Copyright IBM Corp. 2008
+ *
+ * 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/errno.h>
+#include <asm/current.h>
+#include <asm/debug.h>
+#include <asm/ebcdic.h>
+#include <asm/sysinfo.h>
+#include "gaccess.h"
+#include "kvm-s390.h"
+
+static int handle_set_prefix(struct kvm_vcpu *vcpu)
+{
+        int base2 = vcpu->arch.sie_block->ipb >> 28;
+        int disp2 = ((vcpu->arch.sie_block->ipb & 0x0fff0000) >> 16);
+        u64 operand2;
+        u32 address = 0;
+        u8 tmp;
+
+        vcpu->stat.instruction_spx++;
+
+        operand2 = disp2;
+        if (base2)
+                operand2 += vcpu->arch.guest_gprs[base2];
+
+        /* must be word boundary */
+        if (operand2 & 3) {
+                kvm_s390_inject_program_int(vcpu, PGM_SPECIFICATION);
+                goto out;
+        }
+
+        /* get the value */
+        if (get_guest_u32(vcpu, operand2, &address)) {
+                kvm_s390_inject_program_int(vcpu, PGM_ADDRESSING);
+                goto out;
+        }
+
+        address = address & 0x7fffe000u;
+
+        /* make sure that the new value is valid memory */
+        if (copy_from_guest_absolute(vcpu, &tmp, address, 1) ||
+           (copy_from_guest_absolute(vcpu, &tmp, address + PAGE_SIZE, 1))) {
+                kvm_s390_inject_program_int(vcpu, PGM_ADDRESSING);
+                goto out;
+        }
+
+        vcpu->arch.sie_block->prefix = address;
+        vcpu->arch.sie_block->ihcpu = 0xffff;
+
+        VCPU_EVENT(vcpu, 5, "setting prefix to %x", address);
+out:
+        return 0;
+}
+
+static int handle_store_prefix(struct kvm_vcpu *vcpu)
+{
+        int base2 = vcpu->arch.sie_block->ipb >> 28;
+        int disp2 = ((vcpu->arch.sie_block->ipb & 0x0fff0000) >> 16);
+        u64 operand2;
+        u32 address;
+
+        vcpu->stat.instruction_stpx++;
+        operand2 = disp2;
+        if (base2)
+                operand2 += vcpu->arch.guest_gprs[base2];
+
+        /* must be word boundary */
+        if (operand2 & 3) {
+                kvm_s390_inject_program_int(vcpu, PGM_SPECIFICATION);
+                goto out;
+        }
+
+        address = vcpu->arch.sie_block->prefix;
+        address = address & 0x7fffe000u;
+
+        /* get the value */
+        if (put_guest_u32(vcpu, operand2, address)) {
+                kvm_s390_inject_program_int(vcpu, PGM_ADDRESSING);
+                goto out;
+        }
+
+        VCPU_EVENT(vcpu, 5, "storing prefix to %x", address);
+out:
+        return 0;
+}
+
+static int handle_store_cpu_address(struct kvm_vcpu *vcpu)
+{
+        int base2 = vcpu->arch.sie_block->ipb >> 28;
+        int disp2 = ((vcpu->arch.sie_block->ipb & 0x0fff0000) >> 16);
+        u64 useraddr;
+        int rc;
+
+        vcpu->stat.instruction_stap++;
+        useraddr = disp2;
+        if (base2)
+                useraddr += vcpu->arch.guest_gprs[base2];
+
+        if (useraddr & 1) {
+                kvm_s390_inject_program_int(vcpu, PGM_SPECIFICATION);
+                goto out;
+        }
+
+        rc = put_guest_u16(vcpu, useraddr, vcpu->vcpu_id);
+        if (rc == -EFAULT) {
+                kvm_s390_inject_program_int(vcpu, PGM_ADDRESSING);
+                goto out;
+        }
+
+        VCPU_EVENT(vcpu, 5, "storing cpu address to %lx", useraddr);
+out:
+        return 0;
+}
+
+static int handle_skey(struct kvm_vcpu *vcpu)
+{
+        vcpu->stat.instruction_storage_key++;
+        vcpu->arch.sie_block->gpsw.addr -= 4;
+        VCPU_EVENT(vcpu, 4, "%s", "retrying storage key operation");
+        return 0;
+}
+
+static int handle_stsch(struct kvm_vcpu *vcpu)
+{
+        vcpu->stat.instruction_stsch++;
+        VCPU_EVENT(vcpu, 4, "%s", "store subchannel - CC3");
+        /* condition code 3 */
+        vcpu->arch.sie_block->gpsw.mask &= ~(3ul << 44);
+        vcpu->arch.sie_block->gpsw.mask |= (3 & 3ul) << 44;
+        return 0;
+}
+
+static int handle_chsc(struct kvm_vcpu *vcpu)
+{
+        vcpu->stat.instruction_chsc++;
+        VCPU_EVENT(vcpu, 4, "%s", "channel subsystem call - CC3");
+        /* condition code 3 */
+        vcpu->arch.sie_block->gpsw.mask &= ~(3ul << 44);
+        vcpu->arch.sie_block->gpsw.mask |= (3 & 3ul) << 44;
+        return 0;
+}
+
+static unsigned int stfl(void)
+{
+        asm volatile(
+                "       .insn   s,0xb2b10000,0(0)\n" /* stfl */
+                "0:\n"
+                EX_TABLE(0b, 0b));
+        return S390_lowcore.stfl_fac_list;
+}
+
+static int handle_stfl(struct kvm_vcpu *vcpu)
+{
+        unsigned int facility_list = stfl();
+        int rc;
+
+        vcpu->stat.instruction_stfl++;
+        facility_list &= ~(1UL<<24); /* no stfle */
+
+        rc = copy_to_guest(vcpu, offsetof(struct _lowcore, stfl_fac_list),
+                           &facility_list, sizeof(facility_list));
+        if (rc == -EFAULT)
+                kvm_s390_inject_program_int(vcpu, PGM_ADDRESSING);
+        else
+                VCPU_EVENT(vcpu, 5, "store facility list value %x",
+                           facility_list);
+        return 0;
+}
+
+static int handle_stidp(struct kvm_vcpu *vcpu)
+{
+        int base2 = vcpu->arch.sie_block->ipb >> 28;
+        int disp2 = ((vcpu->arch.sie_block->ipb & 0x0fff0000) >> 16);
+        u64 operand2;
+        int rc;
+
+        vcpu->stat.instruction_stidp++;
+        operand2 = disp2;
+        if (base2)
+                operand2 += vcpu->arch.guest_gprs[base2];
+
+        if (operand2 & 7) {
+                kvm_s390_inject_program_int(vcpu, PGM_SPECIFICATION);
+                goto out;
+        }
+
+        rc = put_guest_u64(vcpu, operand2, vcpu->arch.stidp_data);
+        if (rc == -EFAULT) {
+                kvm_s390_inject_program_int(vcpu, PGM_ADDRESSING);
+                goto out;
+        }
+
+        VCPU_EVENT(vcpu, 5, "%s", "store cpu id");
+out:
+        return 0;
+}
+
+static void handle_stsi_3_2_2(struct kvm_vcpu *vcpu, struct sysinfo_3_2_2 *mem)
+{
+        struct float_interrupt *fi = &vcpu->kvm->arch.float_int;
+        int cpus = 0;
+        int n;
+
+        spin_lock_bh(&fi->lock);
+        for (n = 0; n < KVM_MAX_VCPUS; n++)
+                if (fi->local_int[n])
+                        cpus++;
+        spin_unlock_bh(&fi->lock);
+
+        /* deal with other level 3 hypervisors */
+        if (stsi(mem, 3, 2, 2) == -ENOSYS)
+                mem->count = 0;
+        if (mem->count < 8)
+                mem->count++;
+        for (n = mem->count - 1; n > 0 ; n--)
+                memcpy(&mem->vm[n], &mem->vm[n - 1], sizeof(mem->vm[0]));
+
+        mem->vm[0].cpus_total = cpus;
+        mem->vm[0].cpus_configured = cpus;
+        mem->vm[0].cpus_standby = 0;
+        mem->vm[0].cpus_reserved = 0;
+        mem->vm[0].caf = 1000;
+        memcpy(mem->vm[0].name, "KVMguest", 8);
+        ASCEBC(mem->vm[0].name, 8);
+        memcpy(mem->vm[0].cpi, "KVM/Linux       ", 16);
+        ASCEBC(mem->vm[0].cpi, 16);
+}
+
+static int handle_stsi(struct kvm_vcpu *vcpu)
+{
+        int fc = (vcpu->arch.guest_gprs[0] & 0xf0000000) >> 28;
+        int sel1 = vcpu->arch.guest_gprs[0] & 0xff;
+        int sel2 = vcpu->arch.guest_gprs[1] & 0xffff;
+        int base2 = vcpu->arch.sie_block->ipb >> 28;
+        int disp2 = ((vcpu->arch.sie_block->ipb & 0x0fff0000) >> 16);
+        u64 operand2;
+        unsigned long mem;
+
+        vcpu->stat.instruction_stsi++;
+        VCPU_EVENT(vcpu, 4, "stsi: fc: %x sel1: %x sel2: %x", fc, sel1, sel2);
+
+        operand2 = disp2;
+        if (base2)
+                operand2 += vcpu->arch.guest_gprs[base2];
+
+        if (operand2 & 0xfff && fc > 0)
+                return kvm_s390_inject_program_int(vcpu, PGM_SPECIFICATION);
+
+        switch (fc) {
+        case 0:
+                vcpu->arch.guest_gprs[0] = 3 << 28;
+                vcpu->arch.sie_block->gpsw.mask &= ~(3ul << 44);
+                return 0;
+        case 1: /* same handling for 1 and 2 */
+        case 2:
+                mem = get_zeroed_page(GFP_KERNEL);
+                if (!mem)
+                        goto out_fail;
+                if (stsi((void *) mem, fc, sel1, sel2) == -ENOSYS)
+                        goto out_mem;
+                break;
+        case 3:
+                if (sel1 != 2 || sel2 != 2)
+                        goto out_fail;
+                mem = get_zeroed_page(GFP_KERNEL);
+                if (!mem)
+                        goto out_fail;
+                handle_stsi_3_2_2(vcpu, (void *) mem);
+                break;
+        default:
+                goto out_fail;
+        }
+
+        if (copy_to_guest_absolute(vcpu, operand2, (void *) mem, PAGE_SIZE)) {
+                kvm_s390_inject_program_int(vcpu, PGM_ADDRESSING);
+                goto out_mem;
+        }
+        free_page(mem);
+        vcpu->arch.sie_block->gpsw.mask &= ~(3ul << 44);
+        vcpu->arch.guest_gprs[0] = 0;
+        return 0;
+out_mem:
+        free_page(mem);
+out_fail:
+        /* condition code 3 */
+        vcpu->arch.sie_block->gpsw.mask |= 3ul << 44;
+        return 0;
+}
+
+static intercept_handler_t priv_handlers[256] = {
+        [0x02] = handle_stidp,
+        [0x10] = handle_set_prefix,
+        [0x11] = handle_store_prefix,
+        [0x12] = handle_store_cpu_address,
+        [0x29] = handle_skey,
+        [0x2a] = handle_skey,
+        [0x2b] = handle_skey,
+        [0x34] = handle_stsch,
+        [0x5f] = handle_chsc,
+        [0x7d] = handle_stsi,
+        [0xb1] = handle_stfl,
+};
+
+int kvm_s390_handle_priv(struct kvm_vcpu *vcpu)
+{
+        intercept_handler_t handler;
+
+        handler = priv_handlers[vcpu->arch.sie_block->ipa & 0x00ff];
+        if (handler)
+                return handler(vcpu);
+        return -ENOTSUPP;
+}