Am 21.04.2015 um 21:12 schrieb Alexander Graf:
> On 04/20/2015 04:55 PM, Christian Borntraeger wrote:
>> Am 09.04.2015 um 10:51 schrieb Cornelia Huck:
>>> From: Thomas Huth <th...@linux.vnet.ibm.com>
>>>
>>> Add code to make use of the new ioctl for reading from / writing to
>>> virtual guest memory. By using the ioctl, the memory accesses are now
>>> protected with the so-called ipte-lock in the kernel.
>>>
>>> Signed-off-by: Thomas Huth <th...@linux.vnet.ibm.com>
>>> Signed-off-by: Cornelia Huck <cornelia.h...@de.ibm.com>
>> Acked-by: Christian Borntraeger <borntrae...@de.ibm.com>
>>
>>> ---
>>> target-s390x/cpu.h | 7 +++++++
>>> target-s390x/kvm.c | 35 +++++++++++++++++++++++++++++++++++
>>> target-s390x/mmu_helper.c | 9 +++++++++
>>> 3 files changed, 51 insertions(+)
>>>
>>> diff --git a/target-s390x/cpu.h b/target-s390x/cpu.h
>>> index 79bc80b..9c42743 100644
>>> --- a/target-s390x/cpu.h
>>> +++ b/target-s390x/cpu.h
>>> @@ -401,6 +401,8 @@ void kvm_s390_vcpu_interrupt(S390CPU *cpu, struct
>>> kvm_s390_irq *irq);
>>> void kvm_s390_floating_interrupt(struct kvm_s390_irq *irq);
>>> int kvm_s390_inject_flic(struct kvm_s390_irq *irq);
>>> void kvm_s390_access_exception(S390CPU *cpu, uint16_t code, uint64_t
>>> te_code);
>>> +int kvm_s390_mem_op(S390CPU *cpu, vaddr addr, void *hostbuf, int len,
>>> + bool is_write);
>>> int kvm_s390_get_clock(uint8_t *tod_high, uint64_t *tod_clock);
>>> int kvm_s390_set_clock(uint8_t *tod_high, uint64_t *tod_clock);
>>> #else
>>> @@ -418,6 +420,11 @@ static inline int kvm_s390_set_clock(uint8_t
>>> *tod_high, uint64_t *tod_low)
>>> {
>>> return -ENOSYS;
>>> }
>>> +static inline int kvm_s390_mem_op(S390CPU *cpu, vaddr addr, void *hostbuf,
>>> + int len, bool is_write)
>>> +{
>>> + return -ENOSYS;
>>> +}
>>> static inline void kvm_s390_access_exception(S390CPU *cpu, uint16_t code,
>>> uint64_t te_code)
>>> {
>>> diff --git a/target-s390x/kvm.c b/target-s390x/kvm.c
>>> index 619684b..e2ae2b3 100644
>>> --- a/target-s390x/kvm.c
>>> +++ b/target-s390x/kvm.c
>>> @@ -123,6 +123,7 @@ const KVMCapabilityInfo
>>> kvm_arch_required_capabilities[] = {
>>>
>>> static int cap_sync_regs;
>>> static int cap_async_pf;
>>> +static int cap_mem_op;
>>>
>>> static void *legacy_s390_alloc(size_t size, uint64_t *align);
>>>
>>> @@ -247,6 +248,7 @@ int kvm_arch_init(MachineState *ms, KVMState *s)
>>> {
>>> cap_sync_regs = kvm_check_extension(s, KVM_CAP_SYNC_REGS);
>>> cap_async_pf = kvm_check_extension(s, KVM_CAP_ASYNC_PF);
>>> + cap_mem_op = kvm_check_extension(s, KVM_CAP_S390_MEM_OP);
>>>
>>> kvm_s390_enable_cmma(s);
>>>
>>> @@ -550,6 +552,39 @@ int kvm_s390_set_clock(uint8_t *tod_high, uint64_t
>>> *tod_low)
>>> return kvm_vm_ioctl(kvm_state, KVM_SET_DEVICE_ATTR, &attr);
>>> }
>>>
>>> +/**
>>> + * kvm_s390_mem_op:
>>> + * @addr: the logical start address in guest memory
>>> + * @hostbuf: buffer in host memory. NULL = do only checks w/o copying
>>> + * @len: length that should be transfered
>>> + * @is_write: true = write, false = read
>>> + * Returns: 0 on success, non-zero if an exception or error occured
>>> + *
>>> + * Use KVM ioctl to read/write from/to guest memory. An access exception
>>> + * is injected into the vCPU in case of translation errors.
>>> + */
>>> +int kvm_s390_mem_op(S390CPU *cpu, vaddr addr, void *hostbuf, int len,
>>> + bool is_write)
>>> +{
>>> + struct kvm_s390_mem_op mem_op = {
>>> + .gaddr = addr,
>>> + .flags = KVM_S390_MEMOP_F_INJECT_EXCEPTION,
>>> + .size = len,
>>> + .op = is_write ? KVM_S390_MEMOP_LOGICAL_WRITE
>>> + : KVM_S390_MEMOP_LOGICAL_READ,
>>> + .buf = (uint64_t)hostbuf,
>>> + };
>>> +
>>> + if (!cap_mem_op) {
>>> + return -ENOSYS;
>>> + }
>>> + if (!hostbuf) {
>>> + mem_op.flags |= KVM_S390_MEMOP_F_CHECK_ONLY;
>>> + }
>>> +
>>> + return kvm_vcpu_ioctl(CPU(cpu), KVM_S390_MEM_OP, &mem_op);
>>> +}
>>> +
>>> /*
>>> * Legacy layout for s390:
>>> * Older S390 KVM requires the topmost vma of the RAM to be
>>> diff --git a/target-s390x/mmu_helper.c b/target-s390x/mmu_helper.c
>>> index 9b88498..1e7412c 100644
>>> --- a/target-s390x/mmu_helper.c
>>> +++ b/target-s390x/mmu_helper.c
>>> @@ -450,6 +450,15 @@ int s390_cpu_virt_mem_rw(S390CPU *cpu, vaddr laddr,
>>> void *hostbuf,
>>> target_ulong *pages;
>>> int ret;
>>>
>>> + if (kvm_enabled()) {
>>> + ret = kvm_s390_mem_op(cpu, laddr, hostbuf, len, is_write);
>>> + if (ret >= 0) {
>>> + return ret;
>>> + } else if (ret != -ENOSYS) {
>>> + error_printf("kvm_s390_mem_op() failed: %s\n", strerror(-ret));
>
> Won't this spill the logs like crazy when running new qemu on old kernels?
kvm_s390_mem_op will return -ENOSYS if cap_mem_op is not set.
