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+device: 0.754
+KVM: 0.743
+architecture: 0.736
+hypervisor: 0.712
+performance: 0.710
+graphic: 0.691
+ppc: 0.620
+semantic: 0.603
+user-level: 0.572
+files: 0.572
+register: 0.564
+i386: 0.552
+x86: 0.548
+kernel: 0.543
+network: 0.537
+mistranslation: 0.530
+permissions: 0.505
+socket: 0.503
+peripherals: 0.500
+debug: 0.468
+boot: 0.466
+vnc: 0.453
+risc-v: 0.448
+PID: 0.446
+virtual: 0.432
+TCG: 0.418
+VMM: 0.416
+arm: 0.403
+assembly: 0.311
+
+hv-tlbflush malfunctions on Intel host CPUs with neither EPT nor VPID (qemu-kvm)
+
+Enabling hv-tlbflush on older hosts using Intel CPUs supporting VT-x but neither EPT nor VPID will lead to bluescreens on the guest.
+
+It seems KVM only checks if EPT is available, and if it isn't it forcibly uses VPID. If that's *also* not available, it defaults to basically a no-op hypercall, though windows is expecting the TLB to be flushed.
+
+hv-tlbflush is pretty useless on machines not supporting these extensions anyway (only reasonably fix I can see would be to flush the *entire* TLB on tlbflush hypercall in KVM (i.e. a kernel fix), but that would remove any performance benefits), so I would suggest some kind of preliminary check and warning/error if hv-tlbflush is specified on such a host.
+
+All CPUs mentioned in this thread[0] are confirmed to be affected by the bug, and I have successfully reproduced it on an Intel Core2Duo E8500.
+
+[0] https://forum.proxmox.com/threads/windows-guest-bluescreen-with-proxmox-6.56053/
+
+The QEMU project is currently considering to move its bug tracking to
+another system. For this we need to know which bugs are still valid
+and which could be closed already. Thus we are setting older bugs to
+"Incomplete" now.
+
+If you still think this bug report here is valid, then please switch
+the state back to "New" within the next 60 days, otherwise this report
+will be marked as "Expired". Or please mark it as "Fix Released" if
+the problem has been solved with a newer version of QEMU already.
+
+Thank you and sorry for the inconvenience.
+
+
+[Expired for QEMU because there has been no activity for 60 days.]
+