From: Kees Cook <keescook@chromium.org>
To: Sean Christopherson <seanjc@google.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>,
Vitaly Kuznetsov <vkuznets@redhat.com>,
Wanpeng Li <wanpengli@tencent.com>,
Jim Mattson <jmattson@google.com>, Joerg Roedel <joro@8bytes.org>,
kvm@vger.kernel.org, linux-kernel@vger.kernel.org,
Robert Dinse <nanook@eskimo.com>
Subject: Re: [PATCH v2 3/8] KVM: x86: Omit VCPU_REGS_RIP from emulator's _regs array
Date: Tue, 31 May 2022 11:04:05 -0700 [thread overview]
Message-ID: <202205311104.5D8D79E3F2@keescook> (raw)
In-Reply-To: <20220526210817.3428868-4-seanjc@google.com>
On Thu, May 26, 2022 at 09:08:12PM +0000, Sean Christopherson wrote:
> Omit RIP from the emulator's _regs array, which is used only for GPRs,
> i.e. registers that can be referenced via ModRM and/or SIB bytes. The
> emulator uses the dedicated _eip field for RIP, and manually reads from
> _eip to handle RIP-relative addressing.
>
> To avoid an even bigger, slightly more dangerous change, hardcode the
> number of GPRs to 16 for the time being even though 32-bit KVM's emulator
> technically should only have 8 GPRs. Add a TODO to address that in a
> future commit.
>
> See also the comments above the read_gpr() and write_gpr() declarations,
> and obviously the handling in writeback_registers().
>
> No functional change intended.
>
> Signed-off-by: Sean Christopherson <seanjc@google.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
--
Kees Cook
next prev parent reply other threads:[~2022-05-31 18:04 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-05-26 21:08 [PATCH v2 0/8] KVM: x86: Emulator _regs fixes and cleanups Sean Christopherson
2022-05-26 21:08 ` [PATCH v2 1/8] KVM: x86: Grab regs_dirty in local 'unsigned long' Sean Christopherson
2022-05-26 21:08 ` [PATCH v2 2/8] KVM: x86: Harden _regs accesses to guard against buggy input Sean Christopherson
2022-05-26 21:08 ` [PATCH v2 3/8] KVM: x86: Omit VCPU_REGS_RIP from emulator's _regs array Sean Christopherson
2022-05-31 18:04 ` Kees Cook [this message]
2022-05-26 21:08 ` [PATCH v2 4/8] KVM: x86: Use 16-bit fields to track dirty/valid emulator GPRs Sean Christopherson
2022-05-26 21:08 ` [PATCH v2 5/8] KVM: x86: Reduce the number of emulator GPRs to '8' for 32-bit KVM Sean Christopherson
2022-05-31 18:04 ` Kees Cook
2022-05-26 21:08 ` [PATCH v2 6/8] KVM: x86: Bug the VM if the emulator accesses a non-existent GPR Sean Christopherson
2022-05-31 18:06 ` Kees Cook
2022-06-01 8:29 ` Vitaly Kuznetsov
2022-06-02 16:01 ` Sean Christopherson
2022-05-26 21:08 ` [PATCH v2 7/8] KVM: x86: Bug the VM if the emulator generates a bogus exception vector Sean Christopherson
2022-05-31 18:06 ` Kees Cook
2022-06-01 8:31 ` Vitaly Kuznetsov
2022-05-26 21:08 ` [PATCH v2 8/8] KVM: x86: Bug the VM on an out-of-bounds data read Sean Christopherson
2022-05-31 18:06 ` Kees Cook
2022-06-01 8:39 ` Vitaly Kuznetsov
2022-05-26 23:14 ` [PATCH v2 0/8] KVM: x86: Emulator _regs fixes and cleanups Robert Dinse
2022-06-08 12:23 ` Paolo Bonzini
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=202205311104.5D8D79E3F2@keescook \
--to=keescook@chromium.org \
--cc=jmattson@google.com \
--cc=joro@8bytes.org \
--cc=kvm@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=nanook@eskimo.com \
--cc=pbonzini@redhat.com \
--cc=seanjc@google.com \
--cc=vkuznets@redhat.com \
--cc=wanpengli@tencent.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox