https://github.com/torvalds/linux
Revision 95e16b4792b0429f1933872f743410f00e590c55 authored by Paolo Bonzini on 12 October 2021, 15:33:03 UTC, committed by Paolo Bonzini on 22 October 2021, 14:09:13 UTC
The PIO scratch buffer is larger than a single page, and therefore
it is not possible to copy it in a single step to vcpu->arch/pio_data.
Bound each call to emulator_pio_in/out to a single page; keep
track of how many I/O operations are left in vcpu->arch.sev_pio_count,
so that the operation can be restarted in the complete_userspace_io
callback.

For OUT, this means that the previous kvm_sev_es_outs implementation
becomes an iterator of the loop, and we can consume the sev_pio_data
buffer before leaving to userspace.

For IN, instead, consuming the buffer and decreasing sev_pio_count
is always done in the complete_userspace_io callback, because that
is when the memcpy is done into sev_pio_data.

Cc: stable@vger.kernel.org
Fixes: 7ed9abfe8e9f ("KVM: SVM: Support string IO operations for an SEV-ES guest")
Reported-by: Felix Wilhelm <fwilhelm@google.com>
Reviewed-by: Maxim Levitsky <mlevitsk@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
1 parent 4fa4b38
History
Tip revision: 95e16b4792b0429f1933872f743410f00e590c55 authored by Paolo Bonzini on 12 October 2021, 15:33:03 UTC
KVM: SEV-ES: go over the sev_pio_data buffer in multiple passes if needed
Tip revision: 95e16b4
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