On Mon, 3 Jun 2024 17:02:20 -0700 Zide Chen <zide.c...@intel.com> wrote:
> Currently, if running "-overcommit cpu-pm=on" on hosts that don't > have MWAIT support, the MWAIT/MONITOR feature is advertised to the > guest and executing MWAIT/MONITOR on the guest triggers #UD. > > Typically #UD takes priority over VM-Exit interception checks and > KVM doesn't emulate MONITOR/MWAIT. This causes the guest fail to > boot. > > V2: > - [PATCH 1]: took Thomas' suggestion for more generic fix > - [PATCH 2/3]: no changes > > V3: > - dropped [PATCH 1/3]. Took the simpler approach not to re-order > cpu_exec_realizefn() call. > - changed patch title in [PATCH V3 1/2] > - don't set CPUID_EXT_MONITOR in kvm_cpu_realizefn() on top of above we should make make -overcommit cpu-pm=on to error out if KVM_X86_DISABLE_EXITS_MWAIT is not supported/failed if we don't do this user gets false assumption that cpu-pm=on works as expected, and instead of effective CPU usage/IPI delivery all they get is a storm of mwait exits. > > Zide Chen (2): > vl: Allow multiple -overcommit commands > target/i386: Advertise MWAIT iff host supports > > system/vl.c | 4 ++-- > target/i386/host-cpu.c | 12 ------------ > target/i386/kvm/kvm-cpu.c | 11 +++++++++-- > 3 files changed, 11 insertions(+), 16 deletions(-) >
