Messages in this thread | | | From | Dan Williams <> | Date | Mon, 24 May 2021 19:49:38 -0700 | Subject | Re: [RFC v2-fix-v2 2/2] x86/tdx: Ignore WBINVD instruction for TDX guest |
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On Mon, May 24, 2021 at 7:13 PM Andi Kleen <ak@linux.intel.com> wrote: [..] > > ...to explicitly error out a wbinvd use case before data is altered > > and wbinvd is needed. > > I don't see any point of all of this. We really just want to be the same > as KVM. Not get into the business of patching a bazillion sub systems > that cannot be used in TDX anyways.
Please let's not start this patch off with dubious claims of safety afforded by IgnorePAT. Instead make the true argument that wbinvd is known to be problematic in guests and for that reason many bare metal use cases that require wbinvd have not been ported to guests (like PMEM unlock), and others that only use wbinvd to opportunistically enforce a cache state (like ACPI sleep states) do not see ill effects from missing wbinvd. Given KVM ships with a policy to elide wbinvd in many scenarios adopt the same policy for TDX guests.
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