From: Michael Kelley via Virtualization <virtualization@lists.linux-foundation.org>
To: Wei Liu <wei.liu@kernel.org>
Cc: "open list:GENERIC INCLUDE/ASM HEADER FILES"
<linux-arch@vger.kernel.org>,
Linux on Hyper-V List <linux-hyperv@vger.kernel.org>,
Stephen Hemminger <sthemmin@microsoft.com>,
"pasha.tatashin@soleen.com" <pasha.tatashin@soleen.com>,
Arnd Bergmann <arnd@arndb.de>,
Lillian Grassin-Drake <Lillian.GrassinDrake@microsoft.com>,
"maintainer:X86 ARCHITECTURE \(32-BIT AND 64-BIT\)"
<x86@kernel.org>,
Linux Kernel List <linux-kernel@vger.kernel.org>,
"virtualization@lists.linux-foundation.org"
<virtualization@lists.linux-foundation.org>,
Ingo Molnar <mingo@redhat.com>,
Thomas Gleixner <tglx@linutronix.de>,
"H. Peter Anvin" <hpa@zytor.com>,
Nuno Das Neves <nunodasneves@linux.microsoft.com>,
Borislav Petkov <bp@alien8.de>,
Sunil Muthuswamy <sunilmut@microsoft.com>,
Vineeth Pillai <viremana@linux.microsoft.com>,
Haiyang Zhang <haiyangz@microsoft.com>
Subject: RE: [PATCH v5 07/16] x86/hyperv: extract partition ID from Microsoft Hypervisor if necessary
Date: Thu, 4 Feb 2021 16:33:49 +0000 [thread overview]
Message-ID: <MWHPR21MB159300985570258E73E208D1D7B39@MWHPR21MB1593.namprd21.prod.outlook.com> (raw)
In-Reply-To: <20210202150353.6npksy7tobrvfqlt@liuwe-devbox-debian-v2>
From: Wei Liu <wei.liu@kernel.org> Sent: Tuesday, February 2, 2021 7:04 AM
>
> On Tue, Jan 26, 2021 at 12:48:37AM +0000, Michael Kelley wrote:
> > From: Wei Liu <wei.liu@kernel.org> Sent: Wednesday, January 20, 2021 4:01 AM
> > >
> > > We will need the partition ID for executing some hypercalls later.
> > >
> > > Signed-off-by: Lillian Grassin-Drake <ligrassi@microsoft.com>
> > > Co-Developed-by: Sunil Muthuswamy <sunilmut@microsoft.com>
> > > Signed-off-by: Wei Liu <wei.liu@kernel.org>
> > > ---
> > > v3:
> > > 1. Make hv_get_partition_id static.
> > > 2. Change code structure a bit.
> > > ---
> > > arch/x86/hyperv/hv_init.c | 27 +++++++++++++++++++++++++++
> > > arch/x86/include/asm/mshyperv.h | 2 ++
> > > include/asm-generic/hyperv-tlfs.h | 6 ++++++
> > > 3 files changed, 35 insertions(+)
> > >
> > > diff --git a/arch/x86/hyperv/hv_init.c b/arch/x86/hyperv/hv_init.c
> > > index 6f4cb40e53fe..fc9941bd8653 100644
> > > --- a/arch/x86/hyperv/hv_init.c
> > > +++ b/arch/x86/hyperv/hv_init.c
> > > @@ -26,6 +26,9 @@
> > > #include <linux/syscore_ops.h>
> > > #include <clocksource/hyperv_timer.h>
> > >
> > > +u64 hv_current_partition_id = ~0ull;
> > > +EXPORT_SYMBOL_GPL(hv_current_partition_id);
> > > +
> > > void *hv_hypercall_pg;
> > > EXPORT_SYMBOL_GPL(hv_hypercall_pg);
> > >
> > > @@ -331,6 +334,25 @@ static struct syscore_ops hv_syscore_ops = {
> > > .resume = hv_resume,
> > > };
> > >
> > > +static void __init hv_get_partition_id(void)
> > > +{
> > > + struct hv_get_partition_id *output_page;
> > > + u16 status;
> > > + unsigned long flags;
> > > +
> > > + local_irq_save(flags);
> > > + output_page = *this_cpu_ptr(hyperv_pcpu_output_arg);
> > > + status = hv_do_hypercall(HVCALL_GET_PARTITION_ID, NULL, output_page) &
> > > + HV_HYPERCALL_RESULT_MASK;
> > > + if (status != HV_STATUS_SUCCESS) {
> >
> > Across the Hyper-V code in Linux, the way we check the hypercall result
> > is very inconsistent. IMHO, the and'ing of hv_do_hypercall() with
> > HV_HYPERCALL_RESULT_MASK so that status can be a u16 is stylistically
> > a bit unusual.
> >
> > I'd like to see the hypercall result being stored into a u64 local variable.
> > Then the subsequent test for the status should 'and' the u64 with
> > HV_HYPERCALL_RESULT_MASK to determine the result code.
> > I've made a note to go fix the places that aren't doing it that way.
> >
>
> I will fold in the following diff in the next version. I will also check
> if there are other instances in this patch series that need fixing.
> Pretty sure there are a few.
>
> diff --git a/arch/x86/hyperv/hv_init.c b/arch/x86/hyperv/hv_init.c
> index fc9941bd8653..6064f64a1295 100644
> --- a/arch/x86/hyperv/hv_init.c
> +++ b/arch/x86/hyperv/hv_init.c
> @@ -337,14 +337,13 @@ static struct syscore_ops hv_syscore_ops = {
> static void __init hv_get_partition_id(void)
> {
> struct hv_get_partition_id *output_page;
> - u16 status;
> + u64 status;
> unsigned long flags;
>
> local_irq_save(flags);
> output_page = *this_cpu_ptr(hyperv_pcpu_output_arg);
> - status = hv_do_hypercall(HVCALL_GET_PARTITION_ID, NULL, output_page) &
> - HV_HYPERCALL_RESULT_MASK;
> - if (status != HV_STATUS_SUCCESS) {
> + status = hv_do_hypercall(HVCALL_GET_PARTITION_ID, NULL, output_page);
> + if ((status & HV_HYPERCALL_RESULT_MASK) != HV_STATUS_SUCCESS) {
> /* No point in proceeding if this failed */
> pr_err("Failed to get partition ID: %d\n", status);
> BUG();
> > > + /* No point in proceeding if this failed */
> > > + pr_err("Failed to get partition ID: %d\n", status);
> > > + BUG();
> > > + }
> > > + hv_current_partition_id = output_page->partition_id;
> > > + local_irq_restore(flags);
> > > +}
> > > +
> > > /*
> > > * This function is to be invoked early in the boot sequence after the
> > > * hypervisor has been detected.
> > > @@ -426,6 +448,11 @@ void __init hyperv_init(void)
> > >
> > > register_syscore_ops(&hv_syscore_ops);
> > >
> > > + if (cpuid_ebx(HYPERV_CPUID_FEATURES) & HV_ACCESS_PARTITION_ID)
> > > + hv_get_partition_id();
> >
> > Another place where the EBX value saved into the ms_hyperv structure
> > could be used.
>
> If you're okay with my response earlier, this will be handled later in
> another patch (series).
>
Yes, that's OK. Andrea Parri's patch series for Isolated VMs is capturing the
EBX value as well.
Michael
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next prev parent reply other threads:[~2021-02-04 16:33 UTC|newest]
Thread overview: 27+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <20210120120058.29138-1-wei.liu@kernel.org>
[not found] ` <20210120120058.29138-3-wei.liu@kernel.org>
2021-01-20 16:03 ` [PATCH v5 02/16] x86/hyperv: detect if Linux is the root partition Pavel Tatashin
2021-01-26 0:31 ` Michael Kelley via Virtualization
[not found] ` <20210120120058.29138-7-wei.liu@kernel.org>
2021-01-20 15:12 ` [PATCH v5 06/16] x86/hyperv: allocate output arg pages if required kernel test robot
2021-01-20 19:44 ` Pavel Tatashin
2021-01-26 0:41 ` Michael Kelley via Virtualization
[not found] ` <20210120120058.29138-2-wei.liu@kernel.org>
2021-01-20 15:57 ` [PATCH v5 01/16] asm-generic/hyperv: change HV_CPU_POWER_MANAGEMENT to HV_CPU_MANAGEMENT Pavel Tatashin
2021-01-26 0:25 ` Michael Kelley via Virtualization
[not found] ` <20210120120058.29138-4-wei.liu@kernel.org>
2021-01-20 16:06 ` [PATCH v5 03/16] Drivers: hv: vmbus: skip VMBus initialization if Linux is root Pavel Tatashin
2021-01-26 0:32 ` Michael Kelley via Virtualization
[not found] ` <20210120120058.29138-5-wei.liu@kernel.org>
2021-01-20 16:08 ` [PATCH v5 04/16] iommu/hyperv: don't setup IRQ remapping when running as root Pavel Tatashin
2021-01-26 0:33 ` Michael Kelley via Virtualization
[not found] ` <20210120120058.29138-6-wei.liu@kernel.org>
2021-01-20 16:13 ` [PATCH v5 05/16] clocksource/hyperv: use MSR-based access if " Pavel Tatashin
2021-01-26 0:34 ` Michael Kelley via Virtualization
[not found] ` <20210120120058.29138-8-wei.liu@kernel.org>
2021-01-26 0:48 ` [PATCH v5 07/16] x86/hyperv: extract partition ID from Microsoft Hypervisor if necessary Michael Kelley via Virtualization
[not found] ` <20210202150353.6npksy7tobrvfqlt@liuwe-devbox-debian-v2>
2021-02-04 16:33 ` Michael Kelley via Virtualization [this message]
[not found] ` <20210120120058.29138-9-wei.liu@kernel.org>
2021-01-26 0:49 ` [PATCH v5 08/16] x86/hyperv: handling hypercall page setup for root Michael Kelley via Virtualization
[not found] ` <20210120120058.29138-10-wei.liu@kernel.org>
2021-01-26 1:20 ` [PATCH v5 09/16] x86/hyperv: provide a bunch of helper functions Michael Kelley via Virtualization
[not found] ` <20210120120058.29138-11-wei.liu@kernel.org>
2021-01-26 1:21 ` [PATCH v5 10/16] x86/hyperv: implement and use hv_smp_prepare_cpus Michael Kelley via Virtualization
[not found] ` <20210120120058.29138-12-wei.liu@kernel.org>
2021-01-26 1:22 ` [PATCH v5 11/16] asm-generic/hyperv: update hv_msi_entry Michael Kelley via Virtualization
[not found] ` <20210120120058.29138-13-wei.liu@kernel.org>
2021-01-26 1:23 ` [PATCH v5 12/16] asm-generic/hyperv: update hv_interrupt_entry Michael Kelley via Virtualization
[not found] ` <20210120120058.29138-14-wei.liu@kernel.org>
2021-01-26 1:26 ` [PATCH v5 13/16] asm-generic/hyperv: introduce hv_device_id and auxiliary structures Michael Kelley via Virtualization
[not found] ` <20210202170248.4hds554cyxpuayqc@liuwe-devbox-debian-v2>
[not found] ` <20210203132601.ftpwgs57qtok47cg@liuwe-devbox-debian-v2>
[not found] ` <CAK8P3a0m8jEij-RdP1PTcNcJW2+mXQ1dA4=s+JLXhnv+NyFiHw@mail.gmail.com>
[not found] ` <20210203140906.g35zr7366hh7p5f3@liuwe-devbox-debian-v2>
2021-02-04 16:46 ` Michael Kelley via Virtualization
[not found] ` <20210120120058.29138-15-wei.liu@kernel.org>
2021-01-26 1:27 ` [PATCH v5 14/16] asm-generic/hyperv: import data structures for mapping device interrupts Michael Kelley via Virtualization
[not found] ` <20210120120058.29138-16-wei.liu@kernel.org>
2021-01-27 5:47 ` [PATCH v5 15/16] x86/hyperv: implement an MSI domain for root partition Michael Kelley via Virtualization
[not found] ` <20210202173153.jkbvwck2vsjlbjbz@liuwe-devbox-debian-v2>
2021-02-02 18:15 ` Michael Kelley via Virtualization
[not found] ` <20210120120058.29138-17-wei.liu@kernel.org>
2021-01-27 5:47 ` [PATCH v5 16/16] iommu/hyperv: setup an IO-APIC IRQ remapping " Michael Kelley via Virtualization
[not found] ` <20210203124700.ugx5vd526455u7lb@liuwe-devbox-debian-v2>
2021-02-04 16:41 ` Michael Kelley via Virtualization
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