From: Bjorn Helgaas <helgaas@kernel.org>
To: Borislav Petkov <bp@alien8.de>
Cc: Michael Kelley <mikelley@microsoft.com>,
hpa@zytor.com, kys@microsoft.com, haiyangz@microsoft.com,
wei.liu@kernel.org, decui@microsoft.com, luto@kernel.org,
peterz@infradead.org, davem@davemloft.net, edumazet@google.com,
kuba@kernel.org, pabeni@redhat.com, lpieralisi@kernel.org,
robh@kernel.org, kw@linux.com, bhelgaas@google.com,
arnd@arndb.de, hch@infradead.org, m.szyprowski@samsung.com,
robin.murphy@arm.com, thomas.lendacky@amd.com,
brijesh.singh@amd.com, tglx@linutronix.de, mingo@redhat.com,
dave.hansen@linux.intel.com, Tianyu.Lan@microsoft.com,
kirill.shutemov@linux.intel.com,
sathyanarayanan.kuppuswamy@linux.intel.com, ak@linux.intel.com,
isaku.yamahata@intel.com, dan.j.williams@intel.com,
jane.chu@oracle.com, seanjc@google.com, tony.luck@intel.com,
x86@kernel.org, linux-kernel@vger.kernel.org,
linux-hyperv@vger.kernel.org, netdev@vger.kernel.org,
linux-pci@vger.kernel.org, linux-arch@vger.kernel.org,
iommu@lists.linux.dev
Subject: Re: [Patch v4 04/13] x86/mm: Handle decryption/re-encryption of bss_decrypted consistently
Date: Thu, 29 Dec 2022 10:54:31 -0600 [thread overview]
Message-ID: <20221229165431.GA611286@bhelgaas> (raw)
In-Reply-To: <Y62FbJ1rZ6TVUgml@zn.tnic>
On Thu, Dec 29, 2022 at 01:17:48PM +0100, Borislav Petkov wrote:
> On Thu, Dec 01, 2022 at 07:30:22PM -0800, Michael Kelley wrote:
> > Current code in sme_postprocess_startup() decrypts the bss_decrypted
> > section when sme_me_mask is non-zero. But code in
> > mem_encrypt_free_decrypted_mem() re-encrypts the unused portion based
> > on CC_ATTR_MEM_ENCRYPT. In a Hyper-V guest VM using vTOM, these
> > conditions are not equivalent as sme_me_mask is always zero when
> > using vTOM. Consequently, mem_encrypt_free_decrypted_mem() attempts
> > to re-encrypt memory that was never decrypted.
> >
> > Fix this in mem_encrypt_free_decrypted_mem() by conditioning the
> > re-encryption on the same test for non-zero sme_me_mask. Hyper-V
> > guests using vTOM don't need the bss_decrypted section to be
> > decrypted, so skipping the decryption/re-encryption doesn't cause
> > a problem.
>
> Lemme simplify the formulations a bit:
>
> "sme_postprocess_startup() decrypts the bss_decrypted ection when me_mask
> sme_is non-zero.
s/ection/section/
(In case you copy/paste this text without noticing the typo)
next prev parent reply other threads:[~2022-12-29 16:54 UTC|newest]
Thread overview: 39+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-12-02 3:30 [Patch v4 00/13] Add PCI pass-thru support to Hyper-V Confidential VMs Michael Kelley
2022-12-02 3:30 ` [Patch v4 01/13] x86/ioapic: Gate decrypted mapping on cc_platform_has() attribute Michael Kelley
2022-12-06 19:22 ` Borislav Petkov
2022-12-06 19:54 ` Michael Kelley (LINUX)
2022-12-29 11:39 ` Borislav Petkov
2022-12-29 16:02 ` Michael Kelley (LINUX)
2022-12-06 19:27 ` Sathyanarayanan Kuppuswamy
2022-12-02 3:30 ` [Patch v4 02/13] x86/hyperv: Reorder code in prep for subsequent patch Michael Kelley
2022-12-02 3:30 ` [Patch v4 03/13] Drivers: hv: Explicitly request decrypted in vmap_pfn() calls Michael Kelley
2022-12-29 12:05 ` Borislav Petkov
2022-12-02 3:30 ` [Patch v4 04/13] x86/mm: Handle decryption/re-encryption of bss_decrypted consistently Michael Kelley
2022-12-29 12:17 ` Borislav Petkov
2022-12-29 16:25 ` Michael Kelley (LINUX)
2023-01-09 19:10 ` Borislav Petkov
2023-01-09 19:14 ` Michael Kelley (LINUX)
2022-12-29 16:54 ` Bjorn Helgaas [this message]
2022-12-29 17:12 ` Borislav Petkov
2022-12-02 3:30 ` [Patch v4 05/13] init: Call mem_encrypt_init() after Hyper-V hypercall init is done Michael Kelley
2022-12-06 19:37 ` Sathyanarayanan Kuppuswamy
2022-12-06 20:13 ` Michael Kelley (LINUX)
2022-12-06 20:30 ` Sathyanarayanan Kuppuswamy
2022-12-02 3:30 ` [Patch v4 06/13] x86/hyperv: Change vTOM handling to use standard coco mechanisms Michael Kelley
2023-01-09 16:38 ` Borislav Petkov
2023-01-09 17:37 ` Michael Kelley (LINUX)
2023-01-09 18:07 ` Borislav Petkov
2022-12-02 3:30 ` [Patch v4 07/13] swiotlb: Remove bounce buffer remapping for Hyper-V Michael Kelley
2023-01-09 18:05 ` Borislav Petkov
2022-12-02 3:30 ` [Patch v4 08/13] Drivers: hv: vmbus: Remove second mapping of VMBus monitor pages Michael Kelley
2022-12-02 3:30 ` [Patch v4 09/13] Drivers: hv: vmbus: Remove second way of mapping ring buffers Michael Kelley
2022-12-02 3:30 ` [Patch v4 10/13] hv_netvsc: Remove second mapping of send and recv buffers Michael Kelley
2022-12-02 3:30 ` [Patch v4 11/13] Drivers: hv: Don't remap addresses that are above shared_gpa_boundary Michael Kelley
2022-12-02 3:30 ` [Patch v4 12/13] PCI: hv: Add hypercalls to read/write MMIO space Michael Kelley
2022-12-02 3:30 ` [Patch v4 13/13] PCI: hv: Enable PCI pass-thru devices in Confidential VMs Michael Kelley
2023-01-09 18:47 ` [Patch v4 00/13] Add PCI pass-thru support to Hyper-V " Borislav Petkov
2023-01-09 19:35 ` Michael Kelley (LINUX)
2023-01-12 14:03 ` Wei Liu
2023-01-19 17:58 ` Dexuan Cui
2023-01-20 11:58 ` Borislav Petkov
2023-01-20 12:42 ` Wei Liu
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