linux/drivers/clocksource/hyperv_timer.c, branch v6.4

clocksource: hyper-v: make sure Invariant-TSC is used if it is available

2023-04-17T19:19:05Z

If Hyper-V TSC page is unavailable and Invariant-TSC is available, currently hyperv_cs_msr (rather than Invariant-TSC) is used by default. Use Invariant-TSC by default by downgrading hyperv_cs_msr.rating in hv_init_tsc_clocksource(), if Invariant-TSC is available. Signed-off-by: Dexuan Cui Reviewed-by: Michael Kelley Link: https://lore.kernel.org/r/20230408210339.15085-1-decui@microsoft.com Signed-off-by: Wei Liu

drivers/clocksource/hyper-v: non ACPI support in hyperv clock

2023-04-17T19:16:22Z

Add a placeholder function for the hv_setup_stimer0_irq API to accommodate systems without ACPI support. Since this function is not utilized on x86/x64 systems and non-ACPI support is only intended for x86/x64 systems, a placeholder function is sufficient for now and can be improved upon if necessary in the future. Signed-off-by: Saurabh Sengar Reviewed-by: Michael Kelley Link: https://lore.kernel.org/r/1679298460-11855-2-git-send-email-ssengar@linux.microsoft.com Signed-off-by: Wei Liu

clocksource: hyper-v: Add TSC page support for root partition

2022-11-28T16:48:20Z

Microsoft Hypervisor root partition has to map the TSC page specified by the hypervisor, instead of providing the page to the hypervisor like it's done in the guest partitions. However, it's too early to map the page when the clock is initialized, so, the actual mapping is happening later. Signed-off-by: Stanislav Kinsburskiy CC: "K. Y. Srinivasan" CC: Haiyang Zhang CC: Wei Liu CC: Dexuan Cui CC: Thomas Gleixner CC: Ingo Molnar CC: Borislav Petkov CC: Dave Hansen CC: x86@kernel.org CC: "H. Peter Anvin" CC: Daniel Lezcano CC: linux-hyperv@vger.kernel.org CC: linux-kernel@vger.kernel.org Reviewed-by: Michael Kelley Reviewed-by: Anirudh Rayabharam Link: https://lore.kernel.org/r/166759443644.385891.15921594265843430260.stgit@skinsburskii-cloud-desktop.internal.cloudapp.net Signed-off-by: Wei Liu

clocksource: hyper-v: Use TSC PFN getter to map vvar page

2022-11-28T16:48:20Z

Instead of converting the virtual address to physical directly. This is a precursor patch for the upcoming support for TSC page mapping into Microsoft Hypervisor root partition, where TSC PFN will be defined by the hypervisor and thus can't be obtained by linear translation of the physical address. Signed-off-by: Stanislav Kinsburskiy CC: Andy Lutomirski CC: Thomas Gleixner CC: Ingo Molnar CC: Borislav Petkov CC: Dave Hansen CC: x86@kernel.org CC: "H. Peter Anvin" CC: "K. Y. Srinivasan" CC: Haiyang Zhang CC: Wei Liu CC: Dexuan Cui CC: Daniel Lezcano CC: linux-kernel@vger.kernel.org CC: linux-hyperv@vger.kernel.org Reviewed-by: Michael Kelley Reviewed-by: Anirudh Rayabharam Link: https://lore.kernel.org/r/166749833939.218190.14095015146003109462.stgit@skinsburskii-cloud-desktop.internal.cloudapp.net Signed-off-by: Wei Liu

clocksource: hyper-v: Introduce TSC PFN getter

2022-11-28T16:48:20Z

And rework the code to use it instead of the physical address, which isn't required by itself. This is a cleanup and precursor patch for upcoming support for TSC page mapping into Microsoft Hypervisor root partition, where TSC PFN will be defined by the hypervisor and not by the kernel. Signed-off-by: Stanislav Kinsburskiy CC: "K. Y. Srinivasan" CC: Haiyang Zhang CC: Wei Liu CC: Dexuan Cui CC: Daniel Lezcano CC: Thomas Gleixner CC: linux-hyperv@vger.kernel.org CC: linux-kernel@vger.kernel.org Reviewed-by: Michael Kelley Reviewed-by: Anirudh Rayabharam Link: https://lore.kernel.org/r/166749833420.218190.2102763345349472395.stgit@skinsburskii-cloud-desktop.internal.cloudapp.net Signed-off-by: Wei Liu

clocksource: hyper-v: Introduce a pointer to TSC page

2022-11-28T16:48:20Z

Will be used later keep the address of the remapped page for the root partition as it will be Microsoft Hypervisor defined (and thus won't be a static address). Signed-off-by: Stanislav Kinsburskiy CC: "K. Y. Srinivasan" CC: Haiyang Zhang CC: Wei Liu CC: Dexuan Cui CC: Daniel Lezcano CC: Thomas Gleixner CC: linux-hyperv@vger.kernel.org CC: linux-kernel@vger.kernel.org Reviewed-by: Michael Kelley Reviewed-by: Anirudh Rayabharam Link: https://lore.kernel.org/r/166749832893.218190.16503272948154953294.stgit@skinsburskii-cloud-desktop.internal.cloudapp.net Signed-off-by: Wei Liu

clocksource/drivers/hyperv: add data structure for reference TSC MSR

2022-11-03T15:50:28Z

Add a data structure to represent the reference TSC MSR similar to other MSRs. This simplifies the code for updating the MSR. Signed-off-by: Anirudh Rayabharam Reviewed-by: Michael Kelley Link: https://lore.kernel.org/r/20221027095729.1676394-2-anrayabh@linux.microsoft.com Signed-off-by: Wei Liu

clocksource: hyper-v: unexport __init-annotated hv_init_clocksource()

2022-06-08T12:27:08Z

EXPORT_SYMBOL and __init is a bad combination because the .init.text section is freed up after the initialization. Hence, modules cannot use symbols annotated __init. The access to a freed symbol may end up with kernel panic. modpost used to detect it, but it has been broken for a decade. Recently, I fixed modpost so it started to warn it again, then this showed up in linux-next builds. There are two ways to fix it: - Remove __init - Remove EXPORT_SYMBOL I chose the latter for this case because the only in-tree call-site, arch/x86/kernel/cpu/mshyperv.c is never compiled as modular. (CONFIG_HYPERVISOR_GUEST is boolean) Fixes: dd2cb348613b ("clocksource/drivers: Continue making Hyper-V clocksource ISA agnostic") Reported-by: Stephen Rothwell Signed-off-by: Masahiro Yamada Reviewed-by: Vitaly Kuznetsov Reviewed-by: Michael Kelley Link: https://lore.kernel.org/r/20220606050238.4162200-1-masahiroy@kernel.org Signed-off-by: Wei Liu

drivers: hv: Decouple Hyper-V clock/timer code from VMbus drivers

2021-07-19T09:24:28Z

Hyper-V clock/timer code in hyperv_timer.c is mostly independent from other VMbus drivers, but building for ARM64 without hyperv_timer.c shows some remaining entanglements. A default implementation of hv_read_reference_counter can just read a Hyper-V synthetic register and be independent of hyperv_timer.c, so move this code out and into hv_common.c. Then it can be used by the timesync driver even if hyperv_timer.c isn't built on a particular architecture. If hyperv_timer.c *is* built, it can override with a faster implementation. Also provide stubs for stimer functions called by the VMbus driver when hyperv_timer.c isn't built. No functional changes. Signed-off-by: Michael Kelley Link: https://lore.kernel.org/r/1626220906-22629-1-git-send-email-mikelley@microsoft.com Signed-off-by: Wei Liu

clocksource/drivers/hyper-v: Re-enable VDSO_CLOCKMODE_HVCLOCK on X86

2021-05-14T12:55:13Z

Mohammed reports (https://bugzilla.kernel.org/show_bug.cgi?id=213029) the commit e4ab4658f1cf ("clocksource/drivers/hyper-v: Handle vDSO differences inline") broke vDSO on x86. The problem appears to be that VDSO_CLOCKMODE_HVCLOCK is an enum value in 'enum vdso_clock_mode' and '#ifdef VDSO_CLOCKMODE_HVCLOCK' branch evaluates to false (it is not a define). Use a dedicated HAVE_VDSO_CLOCKMODE_HVCLOCK define instead. Fixes: e4ab4658f1cf ("clocksource/drivers/hyper-v: Handle vDSO differences inline") Reported-by: Mohammed Gamal Suggested-by: Thomas Gleixner Signed-off-by: Vitaly Kuznetsov Signed-off-by: Thomas Gleixner Reviewed-by: Michael Kelley Link: https://lore.kernel.org/r/20210513073246.1715070-1-vkuznets@redhat.com