From bec2c195f829ff5e7a0e741ca254a2bf8a89fcbb Mon Sep 17 00:00:00 2001 From: mstsirkin Date: Mon, 30 Sep 2013 06:03:59 +0000 Subject: pci: new layout: driver must not write to bits>63 Since we never offer feature bits >63, driver must not ack them. Signed-off-by: Michael S. Tsirkin git-svn-id: https://tools.oasis-open.org/version-control/svn/virtio@46 0c8fb4dd-22a2-4bb5-bc14-6c75a5f43652 --- virtio-v1.0-wd01-part1-specification.txt | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) diff --git a/virtio-v1.0-wd01-part1-specification.txt b/virtio-v1.0-wd01-part1-specification.txt index 1c9df33..f8751ad 100644 --- a/virtio-v1.0-wd01-part1-specification.txt +++ b/virtio-v1.0-wd01-part1-specification.txt @@ -752,8 +752,9 @@ guest_feature_select Selects which Feature Bits does guest_feature field refer to. Value 0x0 selects Feature Bits 0 to 31 Value 0x1 selects Feature Bits 32 to 63 - All other values cause writes to guest_feature to be ignored, - and reads to return 0. + When set to any other value, reads from guest_feature + return 0, writing 0 into guest_feature has no effect, and + writing any other value into guest_feature is an error. guest_feature -- cgit v1.2.3