From e1f9a8e8c90ae54387922e33e5ac4fd759747d01 Mon Sep 17 00:00:00 2001 From: Vitaly Kuznetsov Date: Thu, 2 Sep 2021 11:35:28 +0200 Subject: i386: Implement pseudo 'hv-avic' ('hv-apicv') enlightenment The enlightenment allows to use Hyper-V SynIC with hardware APICv/AVIC enabled. Normally, Hyper-V SynIC disables these hardware features and suggests the guest to use paravirtualized AutoEOI feature. Linux-4.15 gains support for conditional APICv/AVIC disablement, the feature stays on until the guest tries to use AutoEOI feature with SynIC. With 'HV_DEPRECATING_AEOI_RECOMMENDED' bit exposed, modern enough Windows/ Hyper-V versions should follow the recommendation and not use the (unwanted) feature. Signed-off-by: Vitaly Kuznetsov Message-Id: <20210902093530.345756-7-vkuznets@redhat.com> Signed-off-by: Paolo Bonzini --- docs/hyperv.txt | 10 +++++++++- 1 file changed, 9 insertions(+), 1 deletion(-) (limited to 'docs/hyperv.txt') diff --git a/docs/hyperv.txt b/docs/hyperv.txt index 072709a..cd1ea3b 100644 --- a/docs/hyperv.txt +++ b/docs/hyperv.txt @@ -189,7 +189,15 @@ enabled. Requires: hv-vpindex, hv-synic, hv-time, hv-stimer -3.17. hv-no-nonarch-coresharing=on/off/auto +3.18. hv-avic (hv-apicv) +======================= +The enlightenment allows to use Hyper-V SynIC with hardware APICv/AVIC enabled. +Normally, Hyper-V SynIC disables these hardware feature and suggests the guest +to use paravirtualized AutoEOI feature. +Note: enabling this feature on old hardware (without APICv/AVIC support) may +have negative effect on guest's performace. + +3.19. hv-no-nonarch-coresharing=on/off/auto =========================================== This enlightenment tells guest OS that virtual processors will never share a physical core unless they are reported as sibling SMT threads. This information -- cgit v1.1