d21987d709
Without deferred IO support, hyperv_fb driver informs the host to refresh the entire guest frame buffer at fixed rate, e.g. at 20Hz, no matter there is screen update or not. This patch supports deferred IO for screens in graphics mode and also enables the frame buffer on-demand refresh. The highest refresh rate is still set at 20Hz. Currently Hyper-V only takes a physical address from guest as the starting address of frame buffer. This implies the guest must allocate contiguous physical memory for frame buffer. In addition, Hyper-V Gen 2 VMs only accept address from MMIO region as frame buffer address. Due to these limitations on Hyper-V host, we keep a shadow copy of frame buffer in the guest. This means one more copy of the dirty rectangle inside guest when doing the on-demand refresh. This can be optimized in the future with help from host. For now the host performance gain from deferred IO outweighs the shadow copy impact in the guest. Signed-off-by: Wei Hu <weh@microsoft.com> Reviewed-by: Dexuan Cui <decui@microsoft.com> Reviewed-by: Michael Kelley <mikelley@microsoft.com> Signed-off-by: Sasha Levin <sashal@kernel.org> |
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| LICENSES | ||
| arch | ||
| block | ||
| certs | ||
| crypto | ||
| drivers | ||
| fs | ||
| include | ||
| init | ||
| ipc | ||
| kernel | ||
| lib | ||
| mm | ||
| net | ||
| samples | ||
| scripts | ||
| security | ||
| sound | ||
| tools | ||
| usr | ||
| virt | ||
| .clang-format | ||
| .cocciconfig | ||
| .get_maintainer.ignore | ||
| .gitattributes | ||
| .gitignore | ||
| .mailmap | ||
| COPYING | ||
| CREDITS | ||
| Kbuild | ||
| Kconfig | ||
| MAINTAINERS | ||
| Makefile | ||
| README | ||
README
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.