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From: Paolo Bonzini <pbonzini@redhat.com>
To: Marc Orr <marcorr@google.com>
Cc: linux-kernel@vger.kernel.org, kvm@vger.kernel.org,
	fwilhelm@google.com, seanjc@google.com, oupton@google.com,
	stable@vger.kernel.org
Subject: Re: [PATCH 1/8] KVM: SEV-ES: fix length of string I/O
Date: Mon, 25 Oct 2021 10:59:04 +0200	[thread overview]
Message-ID: <707a0a5d-413e-b80d-89be-17bfca8fc44c@redhat.com> (raw)
In-Reply-To: <CAA03e5F8qvkbnPNvDHjrnM1hLs2fu5L_Mxtuhi3T5Y7u+_ydrw@mail.gmail.com>

On 25/10/21 03:31, Marc Orr wrote:
> I could be missing something, but I'm pretty sure that this is wrong.
> The GHCB spec says that `exit_info_2` is the `rep` count. Not the
> string length.
> 
> For example, given a `rep outsw` instruction, with `ECX` set to `8`,
> the rep count written into `SW_EXITINFO2` should be eight x86 words
> (i.e., 16 bytes) and the IO size should be one x86 word (i.e., 2
> bytes). In other words, the code was correct before this patch. This
> patch is incorrectly dividing the rep count by the IO size, causing
> the string IO to be truncated.

Then what's wrong is _also_ the call to setup_vmgexit_scratch, because 
that one definitely expects bytes:

                 scratch_va = kzalloc(len, GFP_KERNEL_ACCOUNT);

Paolo


  reply	other threads:[~2021-10-25  8:59 UTC|newest]

Thread overview: 27+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-10-13 16:56 [PATCH 0/8] KVM: SEV-ES: fixes for string I/O emulation Paolo Bonzini
2021-10-13 16:56 ` [PATCH 1/8] KVM: SEV-ES: fix length of string I/O Paolo Bonzini
2021-10-14 20:13   ` Tom Lendacky
2021-10-21 23:10   ` Maxim Levitsky
2021-10-25  1:31   ` Marc Orr
2021-10-25  8:59     ` Paolo Bonzini [this message]
2021-10-13 16:56 ` [PATCH 2/8] KVM: SEV-ES: rename guest_ins_data to sev_pio_data Paolo Bonzini
2021-10-21 23:12   ` Maxim Levitsky
2021-10-13 16:56 ` [PATCH 3/8] KVM: x86: leave vcpu->arch.pio.count alone in emulator_pio_in_out Paolo Bonzini
2021-10-21 23:12   ` Maxim Levitsky
2021-10-13 16:56 ` [PATCH 4/8] KVM: SEV-ES: clean up kvm_sev_es_ins/outs Paolo Bonzini
2021-10-21 23:14   ` Maxim Levitsky
2021-10-22 16:31     ` Paolo Bonzini
2021-10-13 16:56 ` [PATCH 5/8] KVM: x86: split the two parts of emulator_pio_in Paolo Bonzini
2021-10-21 23:14   ` Maxim Levitsky
2021-10-13 16:56 ` [PATCH 6/8] KVM: x86: remove unnecessary arguments from complete_emulator_pio_in Paolo Bonzini
2021-10-21 23:14   ` Maxim Levitsky
2021-10-13 16:56 ` [PATCH 7/8] KVM: SEV-ES: keep INS functions together Paolo Bonzini
2021-10-21 23:14   ` Maxim Levitsky
2021-10-13 16:56 ` [PATCH 8/8] KVM: SEV-ES: go over the sev_pio_data buffer in multiple passes if needed Paolo Bonzini
2021-10-21 23:15   ` Maxim Levitsky
2021-10-21 17:47 ` [PATCH 0/8] KVM: SEV-ES: fixes for string I/O emulation Paolo Bonzini
2021-10-21 20:04   ` Sean Christopherson
2021-10-21 23:49 ` Sean Christopherson
2021-10-22 13:33   ` Paolo Bonzini
  -- strict thread matches above, loose matches on Subject: below --
2021-10-18 10:21 [PATCH 1/8] KVM: SEV-ES: fix length of string I/O Naresh Kamboju
2021-10-18 10:54 ` Paolo Bonzini

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