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| author | Thomas Huth <thuth@linux.vnet.ibm.com> | 2015-02-06 14:01:21 (GMT) |
|---|---|---|
| committer | Christian Borntraeger <borntraeger@de.ibm.com> | 2015-03-17 15:26:24 (GMT) |
| commit | 41408c28f283b49202ae374b1c42bc8e9b33a048 (patch) | |
| tree | 4acd40bb4bacc760ad3c65c82b5604145d64d437 /arch/s390/kvm/gaccess.c | |
| parent | 664b4973537068402954bee6e2959b858f263a6f (diff) | |
| download | linux-41408c28f283b49202ae374b1c42bc8e9b33a048.tar.xz | |
KVM: s390: Add MEMOP ioctls for reading/writing guest memory
On s390, we've got to make sure to hold the IPTE lock while accessing
logical memory. So let's add an ioctl for reading and writing logical
memory to provide this feature for userspace, too.
The maximum transfer size of this call is limited to 64kB to prevent
that the guest can trigger huge copy_from/to_user transfers. QEMU
currently only requests up to one or two pages so far, so 16*4kB seems
to be a reasonable limit here.
Signed-off-by: Thomas Huth <thuth@linux.vnet.ibm.com>
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
Diffstat (limited to 'arch/s390/kvm/gaccess.c')
| -rw-r--r-- | arch/s390/kvm/gaccess.c | 22 |
1 files changed, 22 insertions, 0 deletions
diff --git a/arch/s390/kvm/gaccess.c b/arch/s390/kvm/gaccess.c index ea38d71..a7559f7 100644 --- a/arch/s390/kvm/gaccess.c +++ b/arch/s390/kvm/gaccess.c @@ -864,6 +864,28 @@ int guest_translate_address(struct kvm_vcpu *vcpu, unsigned long gva, ar_t ar, } /** + * check_gva_range - test a range of guest virtual addresses for accessibility + */ +int check_gva_range(struct kvm_vcpu *vcpu, unsigned long gva, ar_t ar, + unsigned long length, int is_write) +{ + unsigned long gpa; + unsigned long currlen; + int rc = 0; + + ipte_lock(vcpu); + while (length > 0 && !rc) { + currlen = min(length, PAGE_SIZE - (gva % PAGE_SIZE)); + rc = guest_translate_address(vcpu, gva, ar, &gpa, is_write); + gva += currlen; + length -= currlen; + } + ipte_unlock(vcpu); + + return rc; +} + +/** * kvm_s390_check_low_addr_prot_real - check for low-address protection * @gra: Guest real address * |