From: Michael Kelley <mikelley@microsoft.com>
To: 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@lst.de, m.szyprowski@samsung.com,
robin.murphy@arm.com, thomas.lendacky@amd.com,
brijesh.singh@amd.com, tglx@linutronix.de, mingo@redhat.com,
bp@alien8.de, 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
Cc: mikelley@microsoft.com
Subject: [PATCH v5 04/14] x86/mm: Handle decryption/re-encryption of bss_decrypted consistently
Date: Thu, 12 Jan 2023 13:42:23 -0800 [thread overview]
Message-ID: <1673559753-94403-5-git-send-email-mikelley@microsoft.com> (raw)
In-Reply-To: <1673559753-94403-1-git-send-email-mikelley@microsoft.com>
sme_postprocess_startup() decrypts the bss_decrypted section when
sme_me_mask is non-zero.
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.
So check sme_me_mask in mem_encrypt_free_decrypted_mem() too.
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.
Signed-off-by: Michael Kelley <mikelley@microsoft.com>
Reviewed-by: Tom Lendacky <thomas.lendacky@amd.com>
---
arch/x86/mm/mem_encrypt_amd.c | 10 +++++++---
1 file changed, 7 insertions(+), 3 deletions(-)
diff --git a/arch/x86/mm/mem_encrypt_amd.c b/arch/x86/mm/mem_encrypt_amd.c
index 9c4d8db..e0b51c0 100644
--- a/arch/x86/mm/mem_encrypt_amd.c
+++ b/arch/x86/mm/mem_encrypt_amd.c
@@ -513,10 +513,14 @@ void __init mem_encrypt_free_decrypted_mem(void)
npages = (vaddr_end - vaddr) >> PAGE_SHIFT;
/*
- * The unused memory range was mapped decrypted, change the encryption
- * attribute from decrypted to encrypted before freeing it.
+ * If the unused memory range was mapped decrypted, change the encryption
+ * attribute from decrypted to encrypted before freeing it. Base the
+ * re-encryption on the same condition used for the decryption in
+ * sme_postprocess_startup(). Higher level abstractions, such as
+ * CC_ATTR_MEM_ENCRYPT, aren't necessarily equivalent in a Hyper-V VM
+ * using vTOM, where sme_me_mask is always zero.
*/
- if (cc_platform_has(CC_ATTR_MEM_ENCRYPT)) {
+ if (sme_me_mask) {
r = set_memory_encrypted(vaddr, npages);
if (r) {
pr_warn("failed to free unused decrypted pages\n");
--
1.8.3.1
next prev parent reply other threads:[~2023-01-12 21:50 UTC|newest]
Thread overview: 70+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-01-12 21:42 [PATCH v5 00/14] Add PCI pass-thru support to Hyper-V Confidential VMs Michael Kelley
2023-01-12 21:42 ` [PATCH v5 01/14] x86/ioapic: Gate decrypted mapping on cc_platform_has() attribute Michael Kelley
2023-01-12 21:42 ` [PATCH v5 02/14] x86/hyperv: Reorder code to facilitate future work Michael Kelley
2023-01-12 21:42 ` [PATCH v5 03/14] Drivers: hv: Explicitly request decrypted in vmap_pfn() calls Michael Kelley
2023-01-12 21:42 ` Michael Kelley [this message]
2023-01-12 21:42 ` [PATCH v5 05/14] init: Call mem_encrypt_init() after Hyper-V hypercall init is done Michael Kelley
2023-01-12 21:42 ` [PATCH v5 06/14] x86/ioremap: Support hypervisor specified range to map as encrypted Michael Kelley
2023-01-20 20:15 ` Borislav Petkov
2023-01-21 4:10 ` Michael Kelley (LINUX)
2023-01-25 14:55 ` Borislav Petkov
2023-02-02 5:49 ` Michael Kelley (LINUX)
2023-02-07 12:41 ` Borislav Petkov
2023-02-07 19:01 ` Michael Kelley (LINUX)
2023-02-07 19:33 ` Borislav Petkov
2023-02-07 19:48 ` Michael Kelley (LINUX)
2023-02-07 19:54 ` Borislav Petkov
2023-02-07 19:57 ` Michael Kelley (LINUX)
2023-02-08 0:18 ` Michael Kelley (LINUX)
2023-02-08 15:09 ` Dave Hansen
2023-02-09 17:29 ` Michael Kelley (LINUX)
2023-02-08 17:23 ` Dave Hansen
2023-02-09 17:47 ` Michael Kelley (LINUX)
2023-02-10 18:41 ` Sean Christopherson
2023-02-10 18:58 ` Dave Hansen
2023-02-10 19:03 ` Borislav Petkov
2023-02-10 19:15 ` Michael Kelley (LINUX)
2023-02-10 19:36 ` Borislav Petkov
2023-02-10 19:58 ` Dave Hansen
2023-02-10 20:50 ` Sean Christopherson
2023-02-10 20:57 ` Sean Christopherson
2023-02-10 21:27 ` Michael Kelley (LINUX)
2023-02-10 23:47 ` Sean Christopherson
2023-02-14 7:45 ` Michael Kelley (LINUX)
2023-02-16 13:32 ` Borislav Petkov
2023-02-16 16:16 ` Michael Kelley (LINUX)
2023-02-16 17:06 ` Borislav Petkov
2023-02-17 6:16 ` Michael Kelley (LINUX)
2023-02-17 14:55 ` Borislav Petkov
2023-02-22 22:13 ` Sean Christopherson
2023-02-22 22:33 ` Borislav Petkov
2023-02-22 22:54 ` Sean Christopherson
2023-02-22 23:34 ` Borislav Petkov
2023-02-23 1:21 ` Sean Christopherson
2023-02-23 10:45 ` Borislav Petkov
2023-02-23 20:01 ` Michael Kelley (LINUX)
2023-02-23 20:27 ` Dave Hansen
2023-03-06 21:51 ` Borislav Petkov
2023-03-09 11:12 ` David Woodhouse
2023-03-09 11:59 ` Borislav Petkov
2023-03-09 13:00 ` David Woodhouse
2023-03-09 14:19 ` Tom Lendacky
2023-03-09 14:36 ` Jörg Rödel
2023-03-09 14:45 ` Borislav Petkov
2023-03-09 15:45 ` David Woodhouse
2023-03-09 16:34 ` Borislav Petkov
2023-03-10 10:05 ` David Woodhouse
2023-02-23 20:26 ` Dave Hansen
2023-02-23 20:41 ` Dave Hansen
2023-02-23 20:51 ` Michael Kelley (LINUX)
2023-02-23 21:07 ` Sean Christopherson
2023-02-23 21:15 ` Michael Kelley (LINUX)
2023-02-23 21:24 ` Dave Hansen
2023-01-12 21:42 ` [PATCH v5 07/14] x86/hyperv: Change vTOM handling to use standard coco mechanisms Michael Kelley
2023-01-12 21:42 ` [PATCH v5 08/14] swiotlb: Remove bounce buffer remapping for Hyper-V Michael Kelley
2023-01-12 21:42 ` [PATCH v5 09/14] Drivers: hv: vmbus: Remove second mapping of VMBus monitor pages Michael Kelley
2023-01-12 21:42 ` [PATCH v5 10/14] Drivers: hv: vmbus: Remove second way of mapping ring buffers Michael Kelley
2023-01-12 21:42 ` [PATCH v5 11/14] hv_netvsc: Remove second mapping of send and recv buffers Michael Kelley
2023-01-12 21:42 ` [PATCH v5 12/14] Drivers: hv: Don't remap addresses that are above shared_gpa_boundary Michael Kelley
2023-01-12 21:42 ` [PATCH v5 13/14] PCI: hv: Add hypercalls to read/write MMIO space Michael Kelley
2023-01-12 21:42 ` [PATCH v5 14/14] PCI: hv: Enable PCI pass-thru devices in Confidential VMs Michael Kelley
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