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From: Vitaly Kuznetsov <vkuznets@redhat.com>
To: Wei Liu <wei.liu@kernel.org>,
	Linux on Hyper-V List <linux-hyperv@vger.kernel.org>
Cc: virtualization@lists.linux-foundation.org,
	Linux Kernel List <linux-kernel@vger.kernel.org>,
	Michael Kelley <mikelley@microsoft.com>,
	Vineeth Pillai <viremana@linux.microsoft.com>,
	Sunil Muthuswamy <sunilmut@microsoft.com>,
	Nuno Das Neves <nudasnev@microsoft.com>,
	Wei Liu <wei.liu@kernel.org>,
	Lillian Grassin-Drake <ligrassi@microsoft.com>,
	"K. Y. Srinivasan" <kys@microsoft.com>,
	Haiyang Zhang <haiyangz@microsoft.com>,
	Stephen Hemminger <sthemmin@microsoft.com>,
	Thomas Gleixner <tglx@linutronix.de>,
	Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>,
	"maintainer\:X86 ARCHITECTURE \(32-BIT AND 64-BIT\)"
	<x86@kernel.org>, "H. Peter Anvin" <hpa@zytor.com>,
	Arnd Bergmann <arnd@arndb.de>,
	"open list\:GENERIC INCLUDE\/ASM HEADER FILES" 
	<linux-arch@vger.kernel.org>
Subject: Re: [PATCH RFC v1 07/18] x86/hyperv: extract partition ID from Microsoft Hypervisor if necessary
Date: Tue, 15 Sep 2020 12:27:16 +0200	[thread overview]
Message-ID: <87y2lbjpx7.fsf@vitty.brq.redhat.com> (raw)
In-Reply-To: <20200914112802.80611-8-wei.liu@kernel.org>

Wei Liu <wei.liu@kernel.org> writes:

> 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>
> ---
>  arch/x86/hyperv/hv_init.c         | 26 ++++++++++++++++++++++++++
>  arch/x86/include/asm/mshyperv.h   |  2 ++
>  include/asm-generic/hyperv-tlfs.h |  6 ++++++
>  3 files changed, 34 insertions(+)
>
> diff --git a/arch/x86/hyperv/hv_init.c b/arch/x86/hyperv/hv_init.c
> index ebba4be4185d..0eec1ed32023 100644
> --- a/arch/x86/hyperv/hv_init.c
> +++ b/arch/x86/hyperv/hv_init.c
> @@ -30,6 +30,9 @@
>  bool hv_root_partition;
>  EXPORT_SYMBOL_GPL(hv_root_partition);
>  
> +u64 hv_current_partition_id;
> +EXPORT_SYMBOL_GPL(hv_current_partition_id);
> +
>  void *hv_hypercall_pg;
>  EXPORT_SYMBOL_GPL(hv_hypercall_pg);
>  
> @@ -345,6 +348,26 @@ static struct syscore_ops hv_syscore_ops = {
>  	.resume		= hv_resume,
>  };
>  
> +void __init hv_get_partition_id(void)
> +{
> +	struct hv_get_partition_id *output_page;
> +	int 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;

Nit: in this case status is 'u16', we can define it as such (instead of
signed int).

> +	if (status != HV_STATUS_SUCCESS)
> +		pr_err("Failed to get partition ID: %d\n", status);
> +	else
> +		hv_current_partition_id = output_page->partition_id;
> +	local_irq_restore(flags);
> +
> +	/* No point in proceeding if this failed */
> +	BUG_ON(status != HV_STATUS_SUCCESS);
> +}
> +
>  /*
>   * This function is to be invoked early in the boot sequence after the
>   * hypervisor has been detected.
> @@ -440,6 +463,9 @@ void __init hyperv_init(void)
>  
>  	register_syscore_ops(&hv_syscore_ops);
>  
> +	if (hv_root_partition)
> +		hv_get_partition_id();

According to TLFS, partition ID is available when AccessPartitionId
privilege is granted. I'd suggest we check that instead of
hv_root_partition (and we can set hv_current_partition_id to something
like U64_MAX so we know it wasn't acuired). So the BUG_ON condition will
move here:

        hv_get_partition_id();
        BUG_ON(hv_root_partition && hv_current_partition_id == U64_MAX);

> +
>  	return;
>  
>  remove_cpuhp_state:
> diff --git a/arch/x86/include/asm/mshyperv.h b/arch/x86/include/asm/mshyperv.h
> index f5c62140f28d..4039302e0ae9 100644
> --- a/arch/x86/include/asm/mshyperv.h
> +++ b/arch/x86/include/asm/mshyperv.h
> @@ -65,6 +65,8 @@ extern void *hv_hypercall_pg;
>  extern void  __percpu  **hyperv_pcpu_input_arg;
>  extern void  __percpu  **hyperv_pcpu_output_arg;
>  
> +extern u64 hv_current_partition_id;
> +
>  static inline u64 hv_do_hypercall(u64 control, void *input, void *output)
>  {
>  	u64 input_address = input ? virt_to_phys(input) : 0;
> diff --git a/include/asm-generic/hyperv-tlfs.h b/include/asm-generic/hyperv-tlfs.h
> index e6903589a82a..87b1a79b19eb 100644
> --- a/include/asm-generic/hyperv-tlfs.h
> +++ b/include/asm-generic/hyperv-tlfs.h
> @@ -141,6 +141,7 @@ struct ms_hyperv_tsc_page {
>  #define HVCALL_FLUSH_VIRTUAL_ADDRESS_SPACE_EX	0x0013
>  #define HVCALL_FLUSH_VIRTUAL_ADDRESS_LIST_EX	0x0014
>  #define HVCALL_SEND_IPI_EX			0x0015
> +#define HVCALL_GET_PARTITION_ID			0x0046
>  #define HVCALL_GET_VP_REGISTERS			0x0050
>  #define HVCALL_SET_VP_REGISTERS			0x0051
>  #define HVCALL_POST_MESSAGE			0x005c
> @@ -407,6 +408,11 @@ struct hv_tlb_flush_ex {
>  	u64 gva_list[];
>  } __packed;
>  
> +/* HvGetPartitionId hypercall (output only) */
> +struct hv_get_partition_id {
> +	u64 partition_id;
> +} __packed;
> +
>  /* HvRetargetDeviceInterrupt hypercall */
>  union hv_msi_entry {
>  	u64 as_uint64;

-- 
Vitaly


  reply	other threads:[~2020-09-15 10:27 UTC|newest]

Thread overview: 45+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-09-14 11:27 [PATCH RFC v1 00/18] Introducing Linux root partition support for Microsoft Hypervisor Wei Liu
2020-09-14 11:27 ` [PATCH RFC v1 01/18] asm-generic/hyperv: change HV_CPU_POWER_MANAGEMENT to HV_CPU_MANAGEMENT Wei Liu
2020-09-14 11:27 ` [PATCH RFC v1 02/18] x86/hyperv: detect if Linux is the root partition Wei Liu
2020-09-14 11:27 ` [PATCH RFC v1 03/18] Drivers: hv: vmbus: skip VMBus initialization if Linux is root Wei Liu
2020-09-14 11:27 ` [PATCH RFC v1 04/18] iommu/hyperv: don't setup IRQ remapping when running as root Wei Liu
2020-09-18  9:12   ` Joerg Roedel
2020-09-14 11:27 ` [PATCH RFC v1 05/18] clocksource/hyperv: use MSR-based access if " Wei Liu
2020-09-15 10:10   ` Vitaly Kuznetsov
2020-09-15 10:32     ` Wei Liu
2020-09-14 11:27 ` [PATCH RFC v1 06/18] x86/hyperv: allocate output arg pages if required Wei Liu
2020-09-15 10:16   ` Vitaly Kuznetsov
2020-09-15 12:43     ` Wei Liu
2020-09-16 15:42       ` Wei Liu
2020-09-16 16:10         ` Vitaly Kuznetsov
2020-09-14 11:27 ` [PATCH RFC v1 07/18] x86/hyperv: extract partition ID from Microsoft Hypervisor if necessary Wei Liu
2020-09-15 10:27   ` Vitaly Kuznetsov [this message]
2020-09-16 16:32     ` Wei Liu
2020-10-27 12:19       ` Wei Liu
2020-09-14 11:27 ` [PATCH RFC v1 08/18] x86/hyperv: handling hypercall page setup for root Wei Liu
2020-09-15 10:32   ` Vitaly Kuznetsov
2020-09-15 10:37     ` Wei Liu
2020-09-15 11:02       ` Vitaly Kuznetsov
2020-09-15 11:16         ` Wei Liu
2020-09-15 11:23           ` Vitaly Kuznetsov
2020-09-15 11:27             ` Wei Liu
2020-09-16 21:34       ` [EXTERNAL] " Sunil Muthuswamy
2020-09-17 11:06         ` Vitaly Kuznetsov
2020-09-14 11:59 ` [PATCH RFC v1 09/18] x86/hyperv: provide a bunch of helper functions Wei Liu
2020-09-15 11:00   ` Vitaly Kuznetsov
2020-10-27 13:10     ` Wei Liu
2020-09-14 11:59 ` [PATCH RFC v1 10/18] x86/hyperv: implement and use hv_smp_prepare_cpus Wei Liu
2020-09-15 11:14   ` Vitaly Kuznetsov
2020-10-27 13:47     ` Wei Liu
2020-10-27 13:56       ` Wei Liu
2020-09-14 11:59 ` [PATCH RFC v1 11/18] asm-generic/hyperv: update hv_msi_entry Wei Liu
2020-09-14 11:59 ` [PATCH RFC v1 12/18] asm-generic/hyperv: update hv_interrupt_entry Wei Liu
2020-10-01 14:33   ` Rob Herring
2020-09-14 11:59 ` [PATCH RFC v1 13/18] asm-generic/hyperv: introduce hv_device_id and auxiliary structures Wei Liu
2020-09-15 11:16   ` Vitaly Kuznetsov
2020-09-15 11:59     ` Wei Liu
2020-09-14 11:59 ` [PATCH RFC v1 14/18] asm-generic/hyperv: import data structures for mapping device interrupts Wei Liu
2020-09-14 11:59 ` [PATCH RFC v1 15/18] x86/apic/msi: export pci_msi_get_hwirq Wei Liu
2020-09-14 11:59 ` [PATCH RFC v1 16/18] x86/hyperv: implement MSI domain for root partition Wei Liu
2020-09-14 11:59 ` [PATCH RFC v1 17/18] x86/ioapic: export a few functions and data structures via io_apic.h Wei Liu
2020-09-14 11:59 ` [PATCH RFC v1 18/18] x86/hyperv: handle IO-APIC when running as root Wei Liu

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