KVM: x86: KVM_CAP_SYNC_REGS

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This commit implements an enhanced x86 version of S390
KVM_CAP_SYNC_REGS functionality. KVM_CAP_SYNC_REGS "allow[s]
userspace to access certain guest registers without having
to call SET/GET_*REGS”. This reduces ioctl overhead which
is particularly important when userspace is making synchronous
guest state modifications (e.g. when emulating and/or intercepting
instructions).

Originally implemented upstream for the S390, the x86 differences
follow:
- userspace can select the register sets to be synchronized with kvm_run
using bit-flags in the kvm_valid_registers and kvm_dirty_registers
fields.
- vcpu_events is available in addition to the regs and sregs register
sets.

Signed-off-by: Ken Hofsass <hofsass@google.com>
Reviewed-by: David Hildenbrand <david@redhat.com>
[Removed wrapper around check for reserved kvm_valid_regs. - Radim]
Signed-off-by: Radim Krčmář <rkrcmar@redhat.com>

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This commit is contained in:

Ken Hofsass 2018-01-31 16:03:36 -08:00 • committed by Radim Krčmář

parent 7b7e39522a

commit 01643c51bf

3 changed files with 145 additions and 16 deletions

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40

Documentation/virtual/kvm/api.txt

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19

arch/x86/include/uapi/asm/kvm.h

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102

arch/x86/kvm/x86.c

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