While working on some Hyper-V TLB flush improvements and Direct TLB flush
feature for Hyper-V on KVM I experienced Windows Server 2019 crashes on
boot when XMM fast hypercall input feature is advertised. Turns out,
HVCALL_SEND_IPI_EX is also an XMM fast hypercall and returning an error
kills the guest. This is fixed in PATCH4. PATCH3 fixes erroneous capping
of sparse CPU banks for XMM fast TLB flush hypercalls. The problem should
be reproducible with >360 vCPUs.
Vitaly Kuznetsov (4):
KVM: x86: hyper-v: Drop redundant 'ex' parameter from
kvm_hv_send_ipi()
KVM: x86: hyper-v: Drop redundant 'ex' parameter from
kvm_hv_flush_tlb()
KVM: x86: hyper-v: Fix the maximum number of sparse banks for XMM fast
TLB flush hypercalls
KVM: x86: hyper-v: HVCALL_SEND_IPI_EX is an XMM fast hypercall
arch/x86/kvm/hyperv.c | 84 +++++++++++++++++++++++--------------------
1 file changed, 45 insertions(+), 39 deletions(-)
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2.35.1
