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

From: Paolo Bonzini
Date: Sat Apr 17 2021 - 08:47:36 EST

On 07/04/21 00:49, Sean Christopherson wrote:
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.

- 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.


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(-)

Queued, thanks.