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KVM: S390: protvirt: Introduce instruction data area bounce buffer

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Now that we can't access guest memory anymore, we have a dedicated
satellite block that's a bounce buffer for instruction data.

We re-use the memop interface to copy the instruction data to / from
userspace. This lets us re-use a lot of QEMU code which used that
interface to make logical guest memory accesses which are not possible
anymore in protected mode anyway.

Signed-off-by: Janosch Frank <frankja@linux.ibm.com>
Reviewed-by: Thomas Huth <thuth@redhat.com>
Reviewed-by: David Hildenbrand <david@redhat.com>
[borntraeger@de.ibm.com: patch merging, splitting, fixing]
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
This commit is contained in:
Janosch Frank
2019-04-02 09:21:06 +02:00
committed by Christian Borntraeger
parent c8aac2344d
commit 19e1227768
4 changed files with 91 additions and 11 deletions
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9
include/uapi/linux/kvm.h
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@@ -474,12 +474,17 @@ struct kvm_s390_mem_op {
__u32 size; /* amount of bytes */
__u32 op; /* type of operation */
__u64 buf; /* buffer in userspace */
__u8 ar; /* the access register number */
__u8 reserved[31]; /* should be set to 0 */
union {
__u8 ar; /* the access register number */
__u32 sida_offset; /* offset into the sida */
__u8 reserved[32]; /* should be set to 0 */
};
};
/* types for kvm_s390_mem_op->op */
#define KVM_S390_MEMOP_LOGICAL_READ 0
#define KVM_S390_MEMOP_LOGICAL_WRITE 1
#define KVM_S390_MEMOP_SIDA_READ 2
#define KVM_S390_MEMOP_SIDA_WRITE 3
/* flags for kvm_s390_mem_op->flags */
#define KVM_S390_MEMOP_F_CHECK_ONLY (1ULL << 0)
#define KVM_S390_MEMOP_F_INJECT_EXCEPTION (1ULL << 1)