On 5/17/24 18:38, Sean Christopherson wrote:
I've hit this three times now when running KVM-Unit-Tests (I'm pretty sure it's
the EPT test, unsurprisingly). And unless I screwed up my testing, I verified it
still fires with Isaku's fix[*], though I'm suddenly having problems repro'ing.
I'll update tomorrow as to whether I botched my testing of Isaku's fix, or if
there's another bug lurking.
https://lore.kernel.org/all/20240515173209.GD168153@xxxxxxxxxxxxxxxxxxxxx
I cannot reproduce it on a Skylake (Xeon Gold 5120), with or without Isaku's
fix, with either ./runtests.sh or your reproducer line.
However I can reproduce it only if eptad=0 and with the following line:
./x86/run x86/vmx.flat -smp 1 -cpu max,host-phys-bits,+vmx -m 2560 \
-append 'ept_access_test_not_present ept_access_test_read_only'
FWIW, I tried that on RPL, still no failure.
Ok, so it does look like a CPU issue. Even with the fixes you
identified, I don't see any other solution than adding scary text in
Kconfig, defaulting it to "n", and adding an also-very-scary
pr_err_once("...") the first time VMPTRLD is executed with
CONFIG_KVM_INTEL_PROVE_VE.
Paolo
