Messages in this thread | | | Date | Wed, 31 Jan 2024 14:15:08 -0800 | Subject | Re: [PATCH v3] x86/sev: Add support for allowing zero SEV ASIDs. | From | Sean Christopherson <> |
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On Thu, Jan 04, 2024, Ashish Kalra wrote: > From: Ashish Kalra <ashish.kalra@amd.com> > > Some BIOSes allow the end user to set the minimum SEV ASID value > (CPUID 0x8000001F_EDX) to be greater than the maximum number of > encrypted guests, or maximum SEV ASID value (CPUID 0x8000001F_ECX) > in order to dedicate all the SEV ASIDs to SEV-ES or SEV-SNP. > > The SEV support, as coded, does not handle the case where the minimum > SEV ASID value can be greater than the maximum SEV ASID value. > As a result, the following confusing message is issued: > > [ 30.715724] kvm_amd: SEV enabled (ASIDs 1007 - 1006) > > Fix the support to properly handle this case. > > Fixes: 916391a2d1dc ("KVM: SVM: Add support for SEV-ES capability in KVM") > Suggested-by: Sean Christopherson <seanjc@google.com> > Signed-off-by: Ashish Kalra <ashish.kalra@amd.com> > Cc: stable@vger.kernel.org > --- > arch/x86/kvm/svm/sev.c | 40 ++++++++++++++++++++++++----------------
This should be ~3 patches:
1. Convert ASID variables/params to unsigned integers. 2. Return -EINVAL instead of -EBUSY 3. The actual fix here
E.g if #2 breaks userspace (extremely unlikely) then bisection should point at exactly that, not at a commit with a whole pile of unrelated things going on.
I'll send a v4, #1 should also be accompanied by a cleanup of sev_asid_new() to not multiplex the ASID with the return code. It can simply set sev->asid directly, which as a bonus makes sev_asid_new() and sev_asid_free() more symmetric.
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