From 9e6dabeffd1d0ec2aa19aa076c4886067238d442 Mon Sep 17 00:00:00 2001 From: Cornelia Huck Date: Thu, 17 Nov 2011 11:00:41 +0100 Subject: KVM: s390: Fix RUNNING flag misinterpretation CPUSTAT_RUNNING was implemented signifying that a vcpu is not stopped. This is not, however, what the architecture says: RUNNING should be set when the host is acting on the behalf of the guest operating system. CPUSTAT_RUNNING has been changed to be set in kvm_arch_vcpu_load() and to be unset in kvm_arch_vcpu_put(). For signifying stopped state of a vcpu, a host-controlled bit has been used and is set/unset basically on the reverse as the old CPUSTAT_RUNNING bit (including pushing it down into stop handling proper in handle_stop()). Cc: stable@kernel.org Signed-off-by: Cornelia Huck Signed-off-by: Carsten Otte Signed-off-by: Avi Kivity --- arch/s390/kvm/diag.c | 2 +- arch/s390/kvm/intercept.c | 3 ++- arch/s390/kvm/interrupt.c | 1 + arch/s390/kvm/kvm-s390.c | 10 +++++++--- arch/s390/kvm/sigp.c | 6 +++--- 5 files changed, 14 insertions(+), 8 deletions(-) (limited to 'arch/s390/kvm') diff --git a/arch/s390/kvm/diag.c b/arch/s390/kvm/diag.c index 87cedd61be04..8943e82cd4d9 100644 --- a/arch/s390/kvm/diag.c +++ b/arch/s390/kvm/diag.c @@ -70,7 +70,7 @@ static int __diag_ipl_functions(struct kvm_vcpu *vcpu) return -EOPNOTSUPP; } - atomic_clear_mask(CPUSTAT_RUNNING, &vcpu->arch.sie_block->cpuflags); + atomic_set_mask(CPUSTAT_STOPPED, &vcpu->arch.sie_block->cpuflags); 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; diff --git a/arch/s390/kvm/intercept.c b/arch/s390/kvm/intercept.c index c7c51898984e..02434543eabb 100644 --- a/arch/s390/kvm/intercept.c +++ b/arch/s390/kvm/intercept.c @@ -132,7 +132,6 @@ static int handle_stop(struct kvm_vcpu *vcpu) int rc = 0; vcpu->stat.exit_stop_request++; - atomic_clear_mask(CPUSTAT_RUNNING, &vcpu->arch.sie_block->cpuflags); spin_lock_bh(&vcpu->arch.local_int.lock); if (vcpu->arch.local_int.action_bits & ACTION_STORE_ON_STOP) { vcpu->arch.local_int.action_bits &= ~ACTION_STORE_ON_STOP; @@ -149,6 +148,8 @@ static int handle_stop(struct kvm_vcpu *vcpu) } if (vcpu->arch.local_int.action_bits & ACTION_STOP_ON_STOP) { + atomic_set_mask(CPUSTAT_STOPPED, + &vcpu->arch.sie_block->cpuflags); vcpu->arch.local_int.action_bits &= ~ACTION_STOP_ON_STOP; VCPU_EVENT(vcpu, 3, "%s", "cpu stopped"); rc = -EOPNOTSUPP; diff --git a/arch/s390/kvm/interrupt.c b/arch/s390/kvm/interrupt.c index 87c16705b381..278ee009ce65 100644 --- a/arch/s390/kvm/interrupt.c +++ b/arch/s390/kvm/interrupt.c @@ -252,6 +252,7 @@ static void __do_deliver_interrupt(struct kvm_vcpu *vcpu, offsetof(struct _lowcore, restart_psw), sizeof(psw_t)); if (rc == -EFAULT) exception = 1; + atomic_clear_mask(CPUSTAT_STOPPED, &vcpu->arch.sie_block->cpuflags); break; case KVM_S390_PROGRAM_INT: diff --git a/arch/s390/kvm/kvm-s390.c b/arch/s390/kvm/kvm-s390.c index 0bd3bea1e4cd..630ab65b488b 100644 --- a/arch/s390/kvm/kvm-s390.c +++ b/arch/s390/kvm/kvm-s390.c @@ -270,10 +270,12 @@ void kvm_arch_vcpu_load(struct kvm_vcpu *vcpu, int cpu) restore_fp_regs(&vcpu->arch.guest_fpregs); restore_access_regs(vcpu->arch.guest_acrs); gmap_enable(vcpu->arch.gmap); + atomic_set_mask(CPUSTAT_RUNNING, &vcpu->arch.sie_block->cpuflags); } void kvm_arch_vcpu_put(struct kvm_vcpu *vcpu) { + atomic_clear_mask(CPUSTAT_RUNNING, &vcpu->arch.sie_block->cpuflags); gmap_disable(vcpu->arch.gmap); save_fp_regs(&vcpu->arch.guest_fpregs); save_access_regs(vcpu->arch.guest_acrs); @@ -301,7 +303,9 @@ static void kvm_s390_vcpu_initial_reset(struct kvm_vcpu *vcpu) int kvm_arch_vcpu_setup(struct kvm_vcpu *vcpu) { - atomic_set(&vcpu->arch.sie_block->cpuflags, CPUSTAT_ZARCH | CPUSTAT_SM); + atomic_set(&vcpu->arch.sie_block->cpuflags, CPUSTAT_ZARCH | + CPUSTAT_SM | + CPUSTAT_STOPPED); vcpu->arch.sie_block->ecb = 6; vcpu->arch.sie_block->eca = 0xC1002001U; vcpu->arch.sie_block->fac = (int) (long) facilities; @@ -428,7 +432,7 @@ static int kvm_arch_vcpu_ioctl_set_initial_psw(struct kvm_vcpu *vcpu, psw_t psw) { int rc = 0; - if (atomic_read(&vcpu->arch.sie_block->cpuflags) & CPUSTAT_RUNNING) + if (!(atomic_read(&vcpu->arch.sie_block->cpuflags) & CPUSTAT_STOPPED)) rc = -EBUSY; else { vcpu->run->psw_mask = psw.mask; @@ -501,7 +505,7 @@ rerun_vcpu: if (vcpu->sigset_active) sigprocmask(SIG_SETMASK, &vcpu->sigset, &sigsaved); - atomic_set_mask(CPUSTAT_RUNNING, &vcpu->arch.sie_block->cpuflags); + atomic_clear_mask(CPUSTAT_STOPPED, &vcpu->arch.sie_block->cpuflags); BUG_ON(vcpu->kvm->arch.float_int.local_int[vcpu->vcpu_id] == NULL); diff --git a/arch/s390/kvm/sigp.c b/arch/s390/kvm/sigp.c index f815118835f3..4a488a98d7f8 100644 --- a/arch/s390/kvm/sigp.c +++ b/arch/s390/kvm/sigp.c @@ -57,8 +57,8 @@ static int __sigp_sense(struct kvm_vcpu *vcpu, u16 cpu_addr, spin_lock(&fi->lock); if (fi->local_int[cpu_addr] == NULL) rc = 3; /* not operational */ - else if (atomic_read(fi->local_int[cpu_addr]->cpuflags) - & CPUSTAT_RUNNING) { + else if (!(atomic_read(fi->local_int[cpu_addr]->cpuflags) + & CPUSTAT_STOPPED)) { *reg &= 0xffffffff00000000UL; rc = 1; /* status stored */ } else { @@ -251,7 +251,7 @@ static int __sigp_set_prefix(struct kvm_vcpu *vcpu, u16 cpu_addr, u32 address, spin_lock_bh(&li->lock); /* cpu must be in stopped state */ - if (atomic_read(li->cpuflags) & CPUSTAT_RUNNING) { + if (!(atomic_read(li->cpuflags) & CPUSTAT_STOPPED)) { rc = 1; /* incorrect state */ *reg &= SIGP_STAT_INCORRECT_STATE; kfree(inti); -- cgit v1.2.3 From bd59d3a4444e5f941c863db1a7715edf7289e29a Mon Sep 17 00:00:00 2001 From: Cornelia Huck Date: Thu, 17 Nov 2011 11:00:42 +0100 Subject: KVM: s390: handle SIGP sense running intercepts SIGP sense running may cause an intercept on higher level virtualization, so handle it by checking the CPUSTAT_RUNNING flag. Signed-off-by: Cornelia Huck Signed-off-by: Carsten Otte Signed-off-by: Avi Kivity --- arch/s390/include/asm/kvm_host.h | 1 + arch/s390/kvm/kvm-s390.c | 1 + arch/s390/kvm/sigp.c | 39 +++++++++++++++++++++++++++++++++++++++ 3 files changed, 41 insertions(+) (limited to 'arch/s390/kvm') diff --git a/arch/s390/include/asm/kvm_host.h b/arch/s390/include/asm/kvm_host.h index 20f9068cd6b5..b0c235cb6ad5 100644 --- a/arch/s390/include/asm/kvm_host.h +++ b/arch/s390/include/asm/kvm_host.h @@ -139,6 +139,7 @@ struct kvm_vcpu_stat { u32 instruction_stfl; u32 instruction_tprot; u32 instruction_sigp_sense; + u32 instruction_sigp_sense_running; u32 instruction_sigp_external_call; u32 instruction_sigp_emergency; u32 instruction_sigp_stop; diff --git a/arch/s390/kvm/kvm-s390.c b/arch/s390/kvm/kvm-s390.c index 630ab65b488b..0891926ea953 100644 --- a/arch/s390/kvm/kvm-s390.c +++ b/arch/s390/kvm/kvm-s390.c @@ -65,6 +65,7 @@ struct kvm_stats_debugfs_item debugfs_entries[] = { { "instruction_stfl", VCPU_STAT(instruction_stfl) }, { "instruction_tprot", VCPU_STAT(instruction_tprot) }, { "instruction_sigp_sense", VCPU_STAT(instruction_sigp_sense) }, + { "instruction_sigp_sense_running", VCPU_STAT(instruction_sigp_sense_running) }, { "instruction_sigp_external_call", VCPU_STAT(instruction_sigp_external_call) }, { "instruction_sigp_emergency", VCPU_STAT(instruction_sigp_emergency) }, { "instruction_sigp_stop", VCPU_STAT(instruction_sigp_stop) }, diff --git a/arch/s390/kvm/sigp.c b/arch/s390/kvm/sigp.c index 4a488a98d7f8..0a7941d74bc6 100644 --- a/arch/s390/kvm/sigp.c +++ b/arch/s390/kvm/sigp.c @@ -31,9 +31,11 @@ #define SIGP_SET_PREFIX 0x0d #define SIGP_STORE_STATUS_ADDR 0x0e #define SIGP_SET_ARCH 0x12 +#define SIGP_SENSE_RUNNING 0x15 /* cpu status bits */ #define SIGP_STAT_EQUIPMENT_CHECK 0x80000000UL +#define SIGP_STAT_NOT_RUNNING 0x00000400UL #define SIGP_STAT_INCORRECT_STATE 0x00000200UL #define SIGP_STAT_INVALID_PARAMETER 0x00000100UL #define SIGP_STAT_EXT_CALL_PENDING 0x00000080UL @@ -275,6 +277,38 @@ out_fi: return rc; } +static int __sigp_sense_running(struct kvm_vcpu *vcpu, u16 cpu_addr, + unsigned long *reg) +{ + int rc; + struct kvm_s390_float_interrupt *fi = &vcpu->kvm->arch.float_int; + + if (cpu_addr >= KVM_MAX_VCPUS) + return 3; /* not operational */ + + spin_lock(&fi->lock); + if (fi->local_int[cpu_addr] == NULL) + rc = 3; /* not operational */ + else { + if (atomic_read(fi->local_int[cpu_addr]->cpuflags) + & CPUSTAT_RUNNING) { + /* running */ + rc = 1; + } else { + /* not running */ + *reg &= 0xffffffff00000000UL; + *reg |= SIGP_STAT_NOT_RUNNING; + rc = 0; + } + } + spin_unlock(&fi->lock); + + VCPU_EVENT(vcpu, 4, "sensed running status of cpu %x rc %x", cpu_addr, + rc); + + return rc; +} + int kvm_s390_handle_sigp(struct kvm_vcpu *vcpu) { int r1 = (vcpu->arch.sie_block->ipa & 0x00f0) >> 4; @@ -331,6 +365,11 @@ int kvm_s390_handle_sigp(struct kvm_vcpu *vcpu) rc = __sigp_set_prefix(vcpu, cpu_addr, parameter, &vcpu->arch.guest_gprs[r1]); break; + case SIGP_SENSE_RUNNING: + vcpu->stat.instruction_sigp_sense_running++; + rc = __sigp_sense_running(vcpu, cpu_addr, + &vcpu->arch.guest_gprs[r1]); + break; case SIGP_RESTART: vcpu->stat.instruction_sigp_restart++; /* user space must know about restart */ -- cgit v1.2.3 From 1eddb85f889a5a9fe59ec184e06844716a00aded Mon Sep 17 00:00:00 2001 From: Christian Borntraeger Date: Thu, 17 Nov 2011 11:00:43 +0100 Subject: KVM: s390: Fix tprot locking There is a potential host deadlock in the tprot intercept handling. We must not hold the mmap semaphore while resolving the guest address. If userspace is remapping, then the memory detection in the guest is broken anyway so we can safely separate the address translation from walking the vmas. Signed-off-by: Christian Borntraeger Signed-off-by: Carsten Otte Signed-off-by: Avi Kivity --- arch/s390/kvm/priv.c | 10 ++++++++-- 1 file changed, 8 insertions(+), 2 deletions(-) (limited to 'arch/s390/kvm') diff --git a/arch/s390/kvm/priv.c b/arch/s390/kvm/priv.c index 391626361084..d02638959922 100644 --- a/arch/s390/kvm/priv.c +++ b/arch/s390/kvm/priv.c @@ -336,6 +336,7 @@ static int handle_tprot(struct kvm_vcpu *vcpu) u64 address1 = disp1 + base1 ? vcpu->arch.guest_gprs[base1] : 0; u64 address2 = disp2 + base2 ? vcpu->arch.guest_gprs[base2] : 0; struct vm_area_struct *vma; + unsigned long user_address; vcpu->stat.instruction_tprot++; @@ -349,9 +350,14 @@ static int handle_tprot(struct kvm_vcpu *vcpu) return -EOPNOTSUPP; + /* we must resolve the address without holding the mmap semaphore. + * This is ok since the userspace hypervisor is not supposed to change + * the mapping while the guest queries the memory. Otherwise the guest + * might crash or get wrong info anyway. */ + user_address = (unsigned long) __guestaddr_to_user(vcpu, address1); + down_read(¤t->mm->mmap_sem); - vma = find_vma(current->mm, - (unsigned long) __guestaddr_to_user(vcpu, address1)); + vma = find_vma(current->mm, user_address); if (!vma) { up_read(¤t->mm->mmap_sem); return kvm_s390_inject_program_int(vcpu, PGM_ADDRESSING); -- cgit v1.2.3 From 52e16b185fdd0aeb0522c203e944873e38ac1575 Mon Sep 17 00:00:00 2001 From: Christian Borntraeger Date: Thu, 17 Nov 2011 11:00:44 +0100 Subject: KVM: s390: announce SYNC_MMU KVM on s390 always had a sync mmu. Any mapping change in userspace mapping was always reflected immediately in the guest mapping. - In older code the guest mapping was just an offset - In newer code the last level page table is shared Signed-off-by: Christian Borntraeger Signed-off-by: Carsten Otte Signed-off-by: Avi Kivity --- arch/s390/kvm/kvm-s390.c | 1 + 1 file changed, 1 insertion(+) (limited to 'arch/s390/kvm') diff --git a/arch/s390/kvm/kvm-s390.c b/arch/s390/kvm/kvm-s390.c index 0891926ea953..d1c445732451 100644 --- a/arch/s390/kvm/kvm-s390.c +++ b/arch/s390/kvm/kvm-s390.c @@ -128,6 +128,7 @@ int kvm_dev_ioctl_check_extension(long ext) switch (ext) { case KVM_CAP_S390_PSW: case KVM_CAP_S390_GMAP: + case KVM_CAP_SYNC_MMU: r = 1; break; default: -- cgit v1.2.3