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author | Marc Zyngier <maz@kernel.org> | 2023-04-05 14:48:58 +0300 |
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committer | Marc Zyngier <maz@kernel.org> | 2023-04-05 21:20:23 +0300 |
commit | 0e5c9a9d6548e9b178d4696c696ae4a21c39ae58 (patch) | |
tree | edaae95c99c0540db8de44a759e8f5242be57e68 /Documentation/virt/kvm | |
parent | 60e7dade498eb881bcdf0d9a420c97625f73acc1 (diff) | |
download | linux-0e5c9a9d6548e9b178d4696c696ae4a21c39ae58.tar.xz |
KVM: arm64: Expose SMC/HVC width to userspace
When returning to userspace to handle a SMCCC call, we consistently
set PC to point to the instruction immediately after the HVC/SMC.
However, should userspace need to know the exact address of the
trapping instruction, it needs to know about the *size* of that
instruction. For AArch64, this is pretty easy. For AArch32, this
is a bit more funky, as Thumb has 16bit encodings for both HVC
and SMC.
Expose this to userspace with a new flag that directly derives
from ESR_EL2.IL. Also update the documentation to reflect the PC
state at the point of exit.
Finally, this fixes a small buglet where the hypercall.{args,ret}
fields would not be cleared on exit, and could contain some
random junk.
Reviewed-by: Oliver Upton <oliver.upton@linux.dev>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/86pm8iv8tj.wl-maz@kernel.org
Diffstat (limited to 'Documentation/virt/kvm')
-rw-r--r-- | Documentation/virt/kvm/api.rst | 8 |
1 files changed, 8 insertions, 0 deletions
diff --git a/Documentation/virt/kvm/api.rst b/Documentation/virt/kvm/api.rst index c8ab2f730945..103f945959ed 100644 --- a/Documentation/virt/kvm/api.rst +++ b/Documentation/virt/kvm/api.rst @@ -6244,6 +6244,14 @@ Definition of ``flags``: conduit to initiate the SMCCC call. If this bit is 0 then the guest used the HVC conduit for the SMCCC call. + - ``KVM_HYPERCALL_EXIT_16BIT``: Indicates that the guest used a 16bit + instruction to initiate the SMCCC call. If this bit is 0 then the + guest used a 32bit instruction. An AArch64 guest always has this + bit set to 0. + +At the point of exit, PC points to the instruction immediately following +the trapping instruction. + :: /* KVM_EXIT_TPR_ACCESS */ |