Re: [PATCH v4] block/nvme: introduce PMR support from NVMe 1.4 spec

[Stefan Hajnoczi]

On Fri, Mar 20, 2020 at 02:50:29PM -0700, Andrzej Jakowski wrote:
> This patch introduces support for PMR that has been defined as part of NVMe 
> 1.4
> spec. User can now specify a pmrdev option that should point to 
> HostMemoryBackend.
> pmrdev memory region will subsequently be exposed as PCI BAR 2 in emulated 
> NVMe
> device. Guest OS can perform mmio read and writes to the PMR region that will 
> stay
> persistent across system reboot.
> 
> Signed-off-by: Andrzej Jakowski <address@hidden>
> Reviewed-by: Klaus Jensen <address@hidden>
> ---
> v3:
>  - replaced qemu_msync() use with qemu_ram_writeback() to allow pmem_persist()
>    or qemu_msync() be called depending on configuration [4] (Stefan)
>  - rephrased comments to improve clarity and fixed code style issues [4]
>    (Stefan, Klaus)
> 
> v2:
>  - reworked PMR to use HostMemoryBackend instead of directly mapping PMR
>    backend file into qemu [1] (Stefan)
> 
> v1:
>  - provided support for Bit 1 from PMRWBM register instead of Bit 0 to ensure
>    improved performance in virtualized environment [2] (Stefan)
> 
>  - added check if pmr size is power of two in size [3] (David)
> 
>  - addressed cross compilation build problems reported by CI environment
> 
> [1]: https://lore.kernel.org/qemu-devel/address@hidden/
> [2]: 
> https://nvmexpress.org/wp-content/uploads/NVM-Express-1_4-2019.06.10-Ratified.pdf
> [3]: https://lore.kernel.org/qemu-devel/address@hidden/
> [4]: https://lore.kernel.org/qemu-devel/address@hidden/
> ---
> Persistent Memory Region (PMR) is a new optional feature provided in NVMe 1.4
> specification. This patch implements initial support for it in NVMe driver.
> ---
>  hw/block/Makefile.objs |   2 +-
>  hw/block/nvme.c        | 109 ++++++++++++++++++++++++++
>  hw/block/nvme.h        |   2 +
>  hw/block/trace-events  |   4 +
>  include/block/nvme.h   | 172 +++++++++++++++++++++++++++++++++++++++++
>  5 files changed, 288 insertions(+), 1 deletion(-)

Excellent, thank you!

Reviewed-by: Stefan Hajnoczi <address@hidden>

signature.asc
Description: PGP signature