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Diffstat (limited to 'results/classifier/108/device/1342')
| -rw-r--r-- | results/classifier/108/device/1342 | 39 |
1 files changed, 39 insertions, 0 deletions
diff --git a/results/classifier/108/device/1342 b/results/classifier/108/device/1342 new file mode 100644 index 000000000..61a2cf197 --- /dev/null +++ b/results/classifier/108/device/1342 @@ -0,0 +1,39 @@ +device: 0.933 +graphic: 0.860 +network: 0.811 +vnc: 0.707 +PID: 0.693 +socket: 0.622 +semantic: 0.577 +boot: 0.499 +other: 0.479 +performance: 0.474 +permissions: 0.429 +debug: 0.384 +files: 0.353 +KVM: 0.199 + +Default machine setting of force-legacy=true causes problems for any modern VirtIO device using MMIO +Description of problem: +The default causes problems if you enable any non-legacy VirtIO device which has the VIRTIO_F_VERSION_1 feature bit will not properly read all feature bits. This is because reading VIRTIO_MMIO_VERSION returns VIRT_VERSION_LEGACY which in turn results in the driver not reading all feature bits, e.g. the qtest access: + +``` +static uint64_t qvirtio_mmio_get_features(QVirtioDevice *d) +{ + QVirtioMMIODevice *dev = container_of(d, QVirtioMMIODevice, vdev); + uint64_t lo; + uint64_t hi = 0; + + qtest_writel(dev->qts, dev->addr + QVIRTIO_MMIO_HOST_FEATURES_SEL, 0); + lo = qtest_readl(dev->qts, dev->addr + QVIRTIO_MMIO_HOST_FEATURES); + + if (dev->version >= 2) { + qtest_writel(dev->qts, dev->addr + QVIRTIO_MMIO_HOST_FEATURES_SEL, 1); + hi = qtest_readl(dev->qts, dev->addr + QVIRTIO_MMIO_HOST_FEATURES); + } + + return (hi << 32) | lo; +} +``` +Additional information: + |