On 08/11/19 06:14, Aaron Lewis wrote: > The L1 hypervisor may include the IA32_TIME_STAMP_COUNTER MSR in the > vmcs12 MSR VM-exit MSR-store area as a way of determining the highest > TSC value that might have been observed by L2 prior to VM-exit. The > current implementation does not capture a very tight bound on this > value. To tighten the bound, add the IA32_TIME_STAMP_COUNTER MSR to the > vmcs02 VM-exit MSR-store area whenever it appears in the vmcs12 VM-exit > MSR-store area. When L0 processes the vmcs12 VM-exit MSR-store area > during the emulation of an L2->L1 VM-exit, special-case the > IA32_TIME_STAMP_COUNTER MSR, using the value stored in the vmcs02 > VM-exit MSR-store area to derive the value to be stored in the vmcs12 > VM-exit MSR-store area. > > v3 -> v4: > - Squash the final commit with the previous one used to prepare the MSR-store > area. There is no need for this split after all. > > v2 -> v3: > - Rename NR_MSR_ENTRIES to NR_LOADSAVE_MSRS > - Pull setup code for preparing the MSR-store area out of the final commit and > put it in it's own commit (4/5). > - Export vmx_find_msr_index() in the final commit instead of in commit 3/5 as > it isn't until the final commit that we actually use it. > > v1 -> v2: > - Rename function nested_vmx_get_msr_value() to > nested_vmx_get_vmexit_msr_value(). > - Remove unneeded tag 'Change-Id' from commit messages. > > Aaron Lewis (4): > kvm: nested: Introduce read_and_check_msr_entry() > kvm: vmx: Rename NR_AUTOLOAD_MSRS to NR_LOADSTORE_MSRS > kvm: vmx: Rename function find_msr() to vmx_find_msr_index() > KVM: nVMX: Add support for capturing highest observable L2 TSC > > arch/x86/kvm/vmx/nested.c | 136 ++++++++++++++++++++++++++++++++------ > arch/x86/kvm/vmx/vmx.c | 14 ++-- > arch/x86/kvm/vmx/vmx.h | 9 ++- > 3 files changed, 131 insertions(+), 28 deletions(-) > Queued, but it would be good to have a testcase for this, either for kvm-unit-tests or for tools/testing/selftests/kvm. Paolo
