Messages in this thread | | | From | Paolo Bonzini <> | Subject | [PATCH 0/8] KVM: SEV-ES: fixes for string I/O emulation | Date | Wed, 13 Oct 2021 12:56:08 -0400 |
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This series, namely patches 1 and 8, fix two bugs in string I/O emulation for SEV-ES:
- first, the length is completely off for "rep ins" and "rep outs" operation of size > 1. After setup_vmgexit_scratch, svm->ghcb_sa_len is in bytes, but kvm_sev_es_string_io expects the number of PIO operations.
- second, the size of the GHCB buffer can exceed the size of vcpu->arch.pio_data. If that happens, we need to go over the GHCB buffer in multiple passes.
The second bug was reported by Felix Wilhelm. The first was found by me by code inspection; on one hand it seems *too* egregious so I'll be gladly proven wrong on this, on the other hand... I know I'm bad at code review, but not _that_ bad.
Patches 2 to 7 are a bunch of cleanups to emulator_pio_in and emulator_pio_in_out, so that the final SEV code is a little easier to reason on. Just a little, no big promises.
Tested by booting a SEV-ES guest and with "regular" kvm-unit-tests. For SEV-ES I also bounded the limit to 12 bytes, and checked in the resulting trace that both the read and write paths were hit when booting a guest.
Paolo
Paolo Bonzini (8): KVM: SEV-ES: fix length of string I/O KVM: SEV-ES: rename guest_ins_data to sev_pio_data KVM: x86: leave vcpu->arch.pio.count alone in emulator_pio_in_out KVM: SEV-ES: clean up kvm_sev_es_ins/outs KVM: x86: split the two parts of emulator_pio_in KVM: x86: remove unnecessary arguments from complete_emulator_pio_in KVM: SEV-ES: keep INS functions together KVM: SEV-ES: go over the sev_pio_data buffer in multiple passes if needed
arch/x86/include/asm/kvm_host.h | 3 +- arch/x86/kvm/svm/sev.c | 2 +- arch/x86/kvm/x86.c | 136 +++++++++++++++++++++----------- 3 files changed, 95 insertions(+), 46 deletions(-)
-- 2.27.0
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