linux-kernel - [PATCH v2 0/8] ccp: KVM: SVM: Use stack for SEV command buffers

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Date:   Tue,  6 Apr 2021 15:49:44 -0700
From:   Sean Christopherson <seanjc@...gle.com>
To:     Paolo Bonzini <pbonzini@...hat.com>,
        Brijesh Singh <brijesh.singh@....com>,
        Tom Lendacky <thomas.lendacky@....com>,
        John Allen <john.allen@....com>
Cc:     Sean Christopherson <seanjc@...gle.com>,
        Vitaly Kuznetsov <vkuznets@...hat.com>,
        Wanpeng Li <wanpengli@...cent.com>,
        Jim Mattson <jmattson@...gle.com>,
        Joerg Roedel <joro@...tes.org>, kvm@...r.kernel.org,
        linux-crypto@...r.kernel.org, linux-kernel@...r.kernel.org,
        Borislav Petkov <bp@...e.de>,
        Christophe Leroy <christophe.leroy@...roup.eu>
Subject: [PATCH v2 0/8] ccp: KVM: SVM: Use stack for SEV command buffers

This series teaches __sev_do_cmd_locked() to gracefully handle vmalloc'd
command buffers by copying _all_ incoming data pointers to an internal
buffer before sending the command to the PSP.  The SEV driver and KVM are
then converted to use the stack for all command buffers.

Tested everything except sev_ioctl_do_pek_import(), I don't know anywhere
near enough about the PSP to give it the right input.

v2:
  - Rebase to kvm/queue, commit f96be2deac9b ("KVM: x86: Support KVM VMs
    sharing SEV context").
  - Unconditionally copy @data to the internal buffer. [Christophe, Brijesh]
  - Allocate a full page for the buffer. [Brijesh]
  - Drop one set of the "!"s. [Christophe]
  - Use virt_addr_valid() instead of is_vmalloc_addr() for the temporary
    patch (definitely feel free to drop the patch if it's not worth
    backporting). [Christophe]
  - s/intput/input/. [Tom]
  - Add a patch to free "sev" if init fails.  This is not strictly
    necessary (I think; I suck horribly when it comes to the driver
    framework).   But it felt wrong to not free cmd_buf on failure, and
    even more wrong to free cmd_buf but not sev.

v1:
  - https://lkml.kernel.org/r/20210402233702.3291792-1-seanjc@google.com

Sean Christopherson (8):
  crypto: ccp: Free SEV device if SEV init fails
  crypto: ccp: Detect and reject "invalid" addresses destined for PSP
  crypto: ccp: Reject SEV commands with mismatching command buffer
  crypto: ccp: Play nice with vmalloc'd memory for SEV command structs
  crypto: ccp: Use the stack for small SEV command buffers
  crypto: ccp: Use the stack and common buffer for status commands
  crypto: ccp: Use the stack and common buffer for INIT command
  KVM: SVM: Allocate SEV command structures on local stack

 arch/x86/kvm/svm/sev.c       | 262 +++++++++++++----------------------
 drivers/crypto/ccp/sev-dev.c | 197 +++++++++++++-------------
 drivers/crypto/ccp/sev-dev.h |   4 +-
 3 files changed, 196 insertions(+), 267 deletions(-)

-- 
2.31.0.208.g409f899ff0-goog