On 01/05/2018 07:14 AM, Tom Lendacky wrote: > On 1/5/2018 5:14 AM, David Woodhouse wrote: >> On Thu, 2018-01-04 at 09:56 -0800, Tim Chen wrote: >>> cpuid ax=0x7, return rdx bit 26 to indicate presence of this feature >>> IA32_SPEC_CTRL (0x48) and IA32_PRED_CMD (0x49) >>> IA32_SPEC_CTRL, bit0 – Indirect Branch Restricted Speculation (IBRS) >>> IA32_PRED_CMD, bit0 – Indirect Branch Prediction Barrier (IBPB) >> >> In a previous iteration of these patches, hadn't you already merged >> support for the AMD variant? Where'd that go? > > It looks like this series is strictly IBRS related. Even though some of > the IBPB definitions are in here, there isn't support later for indicating > IBPB is in use or any places where IBPB would be used. I was assuming that > there would be another series for IBPB support. Is that the plan?
IBPB is meant to be a separate series. We want to get retpoline and IBRS out first. > > AMD is covered by the IBRS support as is, but we also have support for > the IBPB feature alone, identified by a different CPUID bit. I was > waiting for the IBPB series to see if I needed to submit anything or > whether the patches were included. > Tim
