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From: Randy Dunlap <rdunlap@infradead.org>
To: Kuppuswamy Sathyanarayanan 
	<sathyanarayanan.kuppuswamy@linux.intel.com>,
	Thomas Gleixner <tglx@linutronix.de>,
	Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>,
	Peter Zijlstra <peterz@infradead.org>,
	Andy Lutomirski <luto@kernel.org>,
	Bjorn Helgaas <bhelgaas@google.com>,
	Richard Henderson <rth@twiddle.net>,
	Thomas Bogendoerfer <tsbogend@alpha.franken.de>,
	James E J Bottomley <James.Bottomley@HansenPartnership.com>,
	Helge Deller <deller@gmx.de>,
	"David S . Miller" <davem@davemloft.net>,
	Arnd Bergmann <arnd@arndb.de>, Jonathan Corbet <corbet@lwn.net>,
	"Michael S . Tsirkin" <mst@redhat.com>,
	Paolo Bonzini <pbonzini@redhat.com>,
	David Hildenbrand <david@redhat.com>,
	Andrea Arcangeli <aarcange@redhat.com>,
	Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Peter H Anvin <hpa@zytor.com>,
	Dave Hansen <dave.hansen@intel.com>,
	Tony Luck <tony.luck@intel.com>,
	Dan Williams <dan.j.williams@intel.com>,
	Andi Kleen <ak@linux.intel.com>,
	Kirill Shutemov <kirill.shutemov@linux.intel.com>,
	Sean Christopherson <seanjc@google.com>,
	Kuppuswamy Sathyanarayanan <knsathya@kernel.org>,
	x86@kernel.org, linux-kernel@vger.kernel.org,
	linux-pci@vger.kernel.org, linux-alpha@vger.kernel.org,
	linux-mips@vger.kernel.org, linux-parisc@vger.kernel.org,
	sparclinux@vger.kernel.org, linux-arch@vger.kernel.org,
	linux-doc@vger.kernel.org,
	virtualization@lists.linux-foundation.org
Subject: Re: [PATCH v5 16/16] x86/tdx: Add cmdline option to force use of ioremap_host_shared
Date: Fri, 8 Oct 2021 18:45:26 -0700	[thread overview]
Message-ID: <7b4c3e3e-09e4-3bf8-6e23-77892fb6df02@infradead.org> (raw)
In-Reply-To: <20211009003711.1390019-17-sathyanarayanan.kuppuswamy@linux.intel.com>

On 10/8/21 5:37 PM, Kuppuswamy Sathyanarayanan wrote:
> diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt
> index 91ba391f9b32..0af19cb1a28c 100644
> --- a/Documentation/admin-guide/kernel-parameters.txt
> +++ b/Documentation/admin-guide/kernel-parameters.txt
> @@ -2076,6 +2076,18 @@
>   			1 - Bypass the IOMMU for DMA.
>   			unset - Use value of CONFIG_IOMMU_DEFAULT_PASSTHROUGH.
>   
> +	ioremap_force_shared= [X86_64, CCG]
> +			Force the kernel to use shared memory mappings which do
> +			not use ioremap_host_shared/pcimap_host_shared to opt-in
> +			to shared mappings with the host. This feature is mainly
> +			used by a confidential guest when enabling new drivers
> +			without proper shared memory related changes. Please note
> +			that this option might also allow other non explicitly
> +			enabled drivers to interact with the host in confidential
> +			guest, which could cause other security risks. This option
> +			will also cause BIOS data structures to be shared with the
> +			host, which might open security holes.

Hi,
This cmdline option text should have a little bit more info. Just as an
example/template:

	acpi_apic_instance=	[ACPI, IOAPIC]
			Format: <int>
			2: use 2nd APIC table, if available
			1,0: use 1st APIC table
			default: 0

So what is expected after the "=" sign?...

thanks.
-- 
~Randy

  reply	other threads:[~2021-10-09  1:45 UTC|newest]

Thread overview: 85+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-10-09  0:36 [PATCH v5 00/16] Add TDX Guest Support (shared-mm support) Kuppuswamy Sathyanarayanan
2021-10-09  0:36 ` [PATCH v5 01/16] x86/mm: Move force_dma_unencrypted() to common code Kuppuswamy Sathyanarayanan
2021-10-20 16:11   ` Tom Lendacky
2021-10-20 16:43     ` Sathyanarayanan Kuppuswamy
2021-10-09  0:36 ` [PATCH v5 02/16] x86/tdx: Get TD execution environment information via TDINFO Kuppuswamy Sathyanarayanan
2021-10-09  0:36 ` [PATCH v5 03/16] x86/tdx: Exclude Shared bit from physical_mask Kuppuswamy Sathyanarayanan
2021-11-05 22:11   ` Sean Christopherson
2021-11-08 14:45     ` Kirill A. Shutemov
2021-10-09  0:36 ` [PATCH v5 04/16] x86/tdx: Make pages shared in ioremap() Kuppuswamy Sathyanarayanan
2021-10-20 16:03   ` Tom Lendacky
2021-10-20 16:41     ` Sathyanarayanan Kuppuswamy
2021-10-09  0:37 ` [PATCH v5 05/16] x86/tdx: Add helper to do MapGPA hypercall Kuppuswamy Sathyanarayanan
2021-10-09  0:37 ` [PATCH v5 06/16] x86/tdx: Make DMA pages shared Kuppuswamy Sathyanarayanan
2021-10-20 16:33   ` Tom Lendacky
2021-10-20 16:45     ` Sathyanarayanan Kuppuswamy
2021-10-20 17:22       ` Tom Lendacky
2021-10-20 17:26         ` Sathyanarayanan Kuppuswamy
2021-10-09  0:37 ` [PATCH v5 07/16] x86/kvm: Use bounce buffers for TD guest Kuppuswamy Sathyanarayanan
2021-10-20 16:39   ` Tom Lendacky
2021-10-20 16:50     ` Sathyanarayanan Kuppuswamy
2021-10-20 17:26       ` Tom Lendacky
2021-10-09  0:37 ` [PATCH v5 08/16] x86/tdx: ioapic: Add shared bit for IOAPIC base address Kuppuswamy Sathyanarayanan
2021-10-09  0:37 ` [PATCH v5 09/16] x86/tdx: Enable shared memory confidential guest flags for TDX guest Kuppuswamy Sathyanarayanan
2021-10-09  0:37 ` [PATCH v5 10/16] PCI: Consolidate pci_iomap_range(), pci_iomap_wc_range() Kuppuswamy Sathyanarayanan
2021-10-09  0:37 ` [PATCH v5 11/16] asm/io.h: Add ioremap_host_shared fallback Kuppuswamy Sathyanarayanan
2021-10-09  0:37 ` [PATCH v5 12/16] PCI: Add pci_iomap_host_shared(), pci_iomap_host_shared_range() Kuppuswamy Sathyanarayanan
2021-10-09  9:53   ` Michael S. Tsirkin
2021-10-09 20:39     ` Dan Williams
2021-10-10 22:11       ` Andi Kleen
2021-10-12 17:42         ` Dan Williams
2021-10-12 18:35           ` Andi Kleen
2021-10-12 21:14             ` Dan Williams
2021-10-12 21:18               ` Michael S. Tsirkin
2021-10-12 21:24                 ` Andi Kleen
2021-10-12 21:28               ` Andi Kleen
2021-10-12 22:00                 ` Dan Williams
2021-10-18 12:13             ` Greg KH
2021-10-12 18:36         ` Reshetova, Elena
2021-10-12 18:38           ` Andi Kleen
2021-10-12 18:57             ` Reshetova, Elena
2021-10-12 19:13               ` Dan Williams
2021-10-12 19:49                 ` Andi Kleen
2021-10-12 21:11           ` Michael S. Tsirkin
2021-10-14  6:32             ` Reshetova, Elena
2021-10-14  6:57               ` Michael S. Tsirkin
2021-10-14  7:27                 ` Reshetova, Elena
2021-10-14  9:26                   ` Michael S. Tsirkin
2021-10-14 12:33                     ` Reshetova, Elena
2021-10-17 22:17                       ` Michael S. Tsirkin
2021-10-14 11:49                   ` Michael S. Tsirkin
2021-10-17 21:52               ` Thomas Gleixner
2021-10-18  7:03                 ` Reshetova, Elena
2021-10-18  0:55         ` Thomas Gleixner
2021-10-18  1:10           ` Thomas Gleixner
2021-10-18 12:08         ` Greg KH
2021-10-10 22:22     ` Andi Kleen
2021-10-11 11:59       ` Michael S. Tsirkin
2021-10-11 17:32         ` Andi Kleen
2021-10-11 18:22           ` Michael S. Tsirkin
2021-10-18 12:15         ` Greg KH
2021-10-18 13:17           ` Michael S. Tsirkin
2021-10-11  7:58   ` Christoph Hellwig
2021-10-11 17:23     ` Andi Kleen
2021-10-11 19:09       ` Michael S. Tsirkin
2021-10-12  5:31         ` Christoph Hellwig
2021-10-12 18:37           ` Andi Kleen
2021-10-09  0:37 ` [PATCH v5 13/16] PCI: Mark MSI data shared Kuppuswamy Sathyanarayanan
2021-10-09  0:37 ` [PATCH v5 14/16] virtio: Use shared mappings for virtio PCI devices Kuppuswamy Sathyanarayanan
2021-10-09  0:37 ` [PATCH v5 15/16] x86/tdx: Implement ioremap_host_shared for x86 Kuppuswamy Sathyanarayanan
2021-10-09  0:37 ` [PATCH v5 16/16] x86/tdx: Add cmdline option to force use of ioremap_host_shared Kuppuswamy Sathyanarayanan
2021-10-09  1:45   ` Randy Dunlap [this message]
2021-10-09  2:10     ` Kuppuswamy, Sathyanarayanan
2021-10-09 11:04   ` Michael S. Tsirkin
2021-10-11  2:39     ` Andi Kleen
2021-10-11 12:04       ` Michael S. Tsirkin
2021-10-11 17:35         ` Andi Kleen
2021-10-11 18:28           ` Michael S. Tsirkin
2021-10-12 17:55             ` Andi Kleen
2021-10-12 20:59               ` Michael S. Tsirkin
2021-10-12 21:18                 ` Andi Kleen
2021-10-12 21:30                   ` Michael S. Tsirkin
2021-10-15  5:50                     ` Andi Kleen
2021-10-15  6:57                       ` Michael S. Tsirkin
2021-10-15 13:34                         ` Andi Kleen
2021-10-17 22:34                           ` Michael S. Tsirkin

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