[RFC/PATCH 08/15 v2] kvm-s390: intercepts for privileged instructions

Carsten Otte
2008-03-22T17:02:50Z

From: Carsten Otte <cotte@de.ibm.com>
From: Christian Borntraeger <borntraeger@de.ibm.com>

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: Carsten Otte <cotte@de.ibm.com>
---
arch/s390/kvm/Makefile | 2
arch/s390/kvm/intercept.c | 1
arch/s390/kvm/kvm-s390.c | 11 +
arch/s390/kvm/kvm-s390.h | 3
arch/s390/kvm/priv.c | 322 ++++++++++++++++++++++++++++++++++++++++++++
include/asm-s390/kvm_host.h | 13 +
6 files changed, 351 insertions(+), 1 deletion(-)

Index: linux-host/arch/s390/kvm/Makefile
===================================================================
--- linux-host.orig/arch/s390/kvm/Makefile
+++ linux-host/arch/s390/kvm/Makefile
@@ -10,5 +10,5 @@ common-objs = $(addprefix ../../../virt/

EXTRA_CFLAGS += -Ivirt/kvm -Iarch/s390/kvm

-kvm-objs := $(common-objs) kvm-s390.o sie64a.o intercept.o interrupt.o
+kvm-objs := $(common-objs) kvm-s390.o sie64a.o intercept.o interrupt.o priv.o
obj-$(CONFIG_KVM) += kvm.o
Index: linux-host/arch/s390/kvm/intercept.c
===================================================================
--- linux-host.orig/arch/s390/kvm/intercept.c
+++ linux-host/arch/s390/kvm/intercept.c
@@ -100,6 +100,7 @@ static int handle_lctl(struct kvm_vcpu *
}

static intercept_handler_t instruction_handlers[256] = {
+ [0xb2] = kvm_s390_handle_priv,
[0xb7] = handle_lctl,
[0xeb] = handle_lctg,
};
Index: linux-host/arch/s390/kvm/kvm-s390.c
===================================================================
--- linux-host.orig/arch/s390/kvm/kvm-s390.c
+++ linux-host/arch/s390/kvm/kvm-s390.c
@@ -48,6 +48,15 @@ struct kvm_stats_debugfs_item debugfs_en
{ "deliver_restart_signal", VCPU_STAT(deliver_restart_signal) },
{ "deliver_program_interruption", VCPU_STAT(deliver_program_int) },
{ "exit_wait_state", VCPU_STAT(exit_wait_state) },
+ { "instruction_stidp", VCPU_STAT(instruction_stidp) },
+ { "instruction_spx", VCPU_STAT(instruction_spx) },
+ { "instruction_stpx", VCPU_STAT(instruction_stpx) },
+ { "instruction_stap", VCPU_STAT(instruction_stap) },
+ { "instruction_storage_key", VCPU_STAT(instruction_storage_key) },
+ { "instruction_stsch", VCPU_STAT(instruction_stsch) },
+ { "instruction_chsc", VCPU_STAT(instruction_chsc) },
+ { "instruction_stsi", VCPU_STAT(instruction_stsi) },
+ { "instruction_stfl", VCPU_STAT(instruction_stfl) },
{ NULL }
};

@@ -249,6 +258,8 @@ int kvm_arch_vcpu_setup(struct kvm_vcpu
vcpu->arch.sie_block->eca = 0xC1002001U;
setup_timer(&vcpu->arch.ckc_timer, kvm_s390_idle_wakeup,
(unsigned long) vcpu);
+ get_cpu_id(&vcpu->arch.cpu_id);
+ vcpu->arch.cpu_id.version = 0xfe;
return 0;
}

Index: linux-host/arch/s390/kvm/kvm-s390.h
===================================================================
--- linux-host.orig/arch/s390/kvm/kvm-s390.h
+++ linux-host/arch/s390/kvm/kvm-s390.h
@@ -47,4 +47,7 @@ int kvm_s390_inject_vm(struct kvm *kvm,
int kvm_s390_inject_vcpu(struct kvm_vcpu *vcpu,
struct kvm_s390_interrupt *s390int);
int kvm_s390_inject_program_int(struct kvm_vcpu *vcpu, u16 code);
+
+/* implemented in priv.c */
+int kvm_s390_handle_priv(struct kvm_vcpu *vcpu);
#endif
Index: linux-host/arch/s390/kvm/priv.c
===================================================================
--- /dev/null
+++ linux-host/arch/s390/kvm/priv.c
@@ -0,0 +1,322 @@
+/*
+ * 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)
+{
+ if (priv_handlers[vcpu->arch.sie_block->ipa & 0x00ff])
+ return priv_handlers[vcpu->arch.sie_block->ipa & 0x00ff]
+ (vcpu);
+ return -ENOTSUPP;
+}
Index: linux-host/include/asm-s390/kvm_host.h
===================================================================
--- linux-host.orig/include/asm-s390/kvm_host.h
+++ linux-host/include/asm-s390/kvm_host.h
@@ -119,6 +119,15 @@ struct kvm_vcpu_stat {
u32 deliver_restart_signal;
u32 deliver_program_int;
u32 exit_wait_state;
+ u32 instruction_stidp;
+ u32 instruction_spx;
+ u32 instruction_stpx;
+ u32 instruction_stap;
+ u32 instruction_storage_key;
+ u32 instruction_stsch;
+ u32 instruction_chsc;
+ u32 instruction_stsi;
+ u32 instruction_stfl;
};

struct io_info {
@@ -188,6 +197,10 @@ struct kvm_vcpu_arch {
unsigned int guest_acrs[NUM_ACRS];
struct local_interrupt local_int;
struct timer_list ckc_timer;
+ union {
+ cpuid_t cpu_id;
+ u64 stidp_data;
+ };
};

struct kvm_vm_stat {