Commit a9bcd1b8 authored by Thomas Huth's avatar Thomas Huth Committed by Cornelia Huck
Browse files

s390x/mmu: Use ioctl for reading and writing from/to guest memory 



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.

[CH: moved error message into kvm_s390_mem_op()]
Signed-off-by: default avatarThomas Huth <thuth@linux.vnet.ibm.com>
Acked-by: default avatarChristian Borntraeger <borntraeger@de.ibm.com>
Signed-off-by: default avatarCornelia Huck <cornelia.huck@de.ibm.com>
parent f07177a5

target-s390x/cpu.h

+7 −0
Original line number Diff line number Diff line
@@ -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)

{

target-s390x/kvm.c

+40 −0
Original line number Diff line number Diff line
@@ -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 +552,44 @@ 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,

    };

    int ret;



    if (!cap_mem_op) {

        return -ENOSYS;

    }

    if (!hostbuf) {

        mem_op.flags |= KVM_S390_MEMOP_F_CHECK_ONLY;

    }



    ret = kvm_vcpu_ioctl(CPU(cpu), KVM_S390_MEM_OP, &mem_op);

    if (ret < 0) {

        error_printf("KVM_S390_MEM_OP failed: %s\n", strerror(-ret));

    }

    return ret;

}



/*

 * Legacy layout for s390:

 * Older S390 KVM requires the topmost vma of the RAM to be

target-s390x/mmu_helper.c

+7 −0
Original line number Diff line number Diff line
@@ -450,6 +450,13 @@ 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;

        }

    }



    nr_pages = (((laddr & ~TARGET_PAGE_MASK) + len - 1) >> TARGET_PAGE_BITS)

               + 1;

    pages = g_malloc(nr_pages * sizeof(*pages));