Messages in this thread | | | Date | Wed, 29 Mar 2023 08:16:52 +0800 | Subject | Re: [RFC PATCH 0/7] SVM guest shadow stack support | From | "Yang, Weijiang" <> |
| |
On 3/29/2023 1:51 AM, John Allen wrote: > On Wed, Jan 25, 2023 at 01:11:44AM +0000, Edgecombe, Rick P wrote: >> On Wed, 2023-01-25 at 00:55 +0000, Sean Christopherson wrote: >>> On Wed, Oct 12, 2022, John Allen wrote: >>>> AMD Zen3 and newer processors support shadow stack, a feature >>>> designed to >>>> protect against ROP (return-oriented programming) attacks in which >>>> an attacker >>>> manipulates return addresses on the call stack in order to execute >>>> arbitrary >>>> code. To prevent this, shadow stacks can be allocated that are only >>>> used by >>>> control transfer and return instructions. When a CALL instruction >>>> is issued, it >>>> writes the return address to both the program stack and the shadow >>>> stack. When >>>> the subsequent RET instruction is issued, it pops the return >>>> address from both >>>> stacks and compares them. If the addresses don't match, a control- >>>> protection >>>> exception is raised. >>>> >>>> Shadow stack and a related feature, Indirect Branch Tracking (IBT), >>>> are >>>> collectively referred to as Control-flow Enforcement Technology >>>> (CET). However, >>>> current AMD processors only support shadow stack and not IBT. >>>> >>>> This series adds support for shadow stack in SVM guests and builds >>>> upon the >>>> support added in the CET guest support patch series [1] and the CET >>>> kernel >>>> patch series [2]. Additional patches are required to support shadow >>>> stack >>>> enabled guests in qemu [3] and glibc [4]. >>>> >>>> [1]: CET guest support patches >>>> >> https://lore.kernel.org/all/20220616084643.19564-1-weijiang.yang@intel.com/ >>>> [2]: Latest CET kernel patches >>>> >> https://lore.kernel.org/all/20220929222936.14584-1-rick.p.edgecombe@intel.com/ >>> That dependency chain makes me sad. >>> >>> Outside of a very shallow comment on the last patch, I don't plan on >>> reviewing >>> this until the kernel side of things gets out of our way. When that >>> finally >>> does happen, I'll definitely prioritize reviewing and merging this >>> and the KVM >>> Intel series. I'd love to see this land. >> I think all KVM needs is a few patches from the beginning of the host >> series (the FPU stuff). At one point Weijiang and I had discussed with >> Paolo and x86 folks that those few could go up with the KVM series if >> desired. > Now that the baremetal series has been accepted, how do we want to > proceed? I think I'd like to send a refreshed version based on the > version that was accpeted, but I'd want to wait to base it on a new > version of Weijiang's kvm/vmx series (if one is planned). > > Weijiang and Rick, > > Are you planning on sending a new version of the kvm/vmx series?
Hi, Allen,
Yes, I'm working on the new version of kvm/vmx series, will cc you when
send it to community.
> > Thanks, > John
| |