Acked: [bionic:linux-azure][PATCH 1/1] Drivers: hv: vmbus: Implement Direct Mode for stimer0

Krzysztof Kozlowski krzysztof.kozlowski at canonical.com
Wed Jul 28 07:28:57 UTC 2021


On 23/07/2021 20:14, Guilherme G. Piccoli wrote:
> From: Michael Kelley <mhkelley at outlook.com>
> 
> BugLink: https://bugs.launchpad.net/bugs/1882623
> 
> The 2016 version of Hyper-V offers the option to operate the guest VM
> per-vcpu stimer's in Direct Mode, which means the timer interupts on its
> own vector rather than queueing a VMbus message. Direct Mode reduces
> timer processing overhead in both the hypervisor and the guest, and
> avoids having timer interrupts pollute the VMbus interrupt stream for
> the synthetic NIC and storage.  This patch enables Direct Mode by
> default on stimer0 when running on a version of Hyper-V that supports
> it.
> 
> In prep for coming support of Hyper-V on ARM64, the arch independent
> portion of the code contains calls to routines that will be populated
> on ARM64 but are not needed and do nothing on x86.
> 
> Signed-off-by: Michael Kelley <mikelley at microsoft.com>
> Signed-off-by: K. Y. Srinivasan <kys at microsoft.com>
> Signed-off-by: Greg Kroah-Hartman <gregkh at linuxfoundation.org>
> (backported from commit 248e742a396e7f00b283f1c56e14b1bef6e3ec56)
> [gpiccoli: context adjustments, specially due to the lack of the
> following commits in our kernel:
> - commit 51d4e5daa328 ("x86/irq: Count Hyper-V reenlightenment interrupts")
> - commit 5a4858032217 ("x86/hyper-v: move hyperv.h out of uapi")
> Note that the hyperv.h uapi file changed to hyperv-tlfs.h not in uapi.]
> Signed-off-by: Guilherme G. Piccoli <gpiccoli at canonical.com>
> ---
>  arch/x86/entry/entry_32.S          |  3 ++
>  arch/x86/entry/entry_64.S          |  3 ++
>  arch/x86/include/asm/hardirq.h     |  3 ++
>  arch/x86/include/asm/hyperv-tlfs.h |  3 ++
>  arch/x86/include/asm/irq_vectors.h |  3 +-
>  arch/x86/include/asm/mshyperv.h    | 13 +++++++
>  arch/x86/kernel/cpu/mshyperv.c     | 40 ++++++++++++++++++++
>  arch/x86/kernel/irq.c              |  7 ++++
>  drivers/hv/hv.c                    | 59 ++++++++++++++++++++++++++++--
>  drivers/hv/hyperv_vmbus.h          |  4 +-
>  10 files changed, 133 insertions(+), 5 deletions(-)
> 


Acked-by: Krzysztof Kozlowski <krzysztof.kozlowski at canonical.com>


Best regards,
Krzysztof



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