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authorVitaly Kuznetsov <vkuznets@redhat.com>2021-09-02 11:35:28 +0200
committerPaolo Bonzini <pbonzini@redhat.com>2021-10-01 19:04:45 +0200
commite1f9a8e8c90ae54387922e33e5ac4fd759747d01 (patch)
treebe75154742d88bbf4c22d17d65d75958da14cabe /docs
parent050716292a63f4969b32cac32b85774521738ef5 (diff)
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 <vkuznets@redhat.com> Message-Id: <20210902093530.345756-7-vkuznets@redhat.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Diffstat (limited to 'docs')
-rw-r--r--docs/hyperv.txt10
1 files changed, 9 insertions, 1 deletions
diff --git a/docs/hyperv.txt b/docs/hyperv.txt
index 072709a68f..cd1ea3bbe9 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