[Deepin-Kernel-SIG] [linux 6.6-y] [Upstream] [Intel] Intel: backport KVM Fix for Clearing SGX EDECCSSA to 6.6

[Avenger-285714]

Description
When SGX EDECCSSA support was added to KVM in commit 16a7fe3 ("KVM/VMX: Allow exposing EDECCSSA user leaf function to KVM guest"), it forgot to clear the X86_FEATURE_SGX_EDECCSSA bit in KVM CPU caps when KVM SGX is disabled. Fix it.

Fixes: 16a7fe3 ("KVM/VMX: Allow exposing EDECCSSA user leaf function to KVM guest")

About the patches
The total patch number is 1:

7efb4d8a392a KVM: VMX: Also clear SGX EDECCSSA in KVM CPU caps when SGX is disabled
Tests

Build successfully for each commit
Kernel selftest - SGX: PASSED
cd tools/testing/selftests/sgx/
make
./test_sgx
Kernel selftest - SGX in VM: PASSED
Function test
Step 1. Original SGX EDECCSSA status in guest
[root@guest ~]# cpuid -1 -l 0x12
CPU:
Software Guard Extensions (SGX) capability (0x12/0):
SGX1 supported = true
SGX2 supported = true
SGX ENCLV E*VIRTCHILD, ESETCONTEXT = false
SGX ENCLS ETRACKC, ERDINFO, ELDBC, ELDUC = false
SGX ENCLU EVERIFYREPORT2 = false
SGX ENCLS EUPDATESVN = false
SGX ENCLU EDECCSSA = true
MISCSELECT.EXINFO supported: #PF & #GP = true
MISCSELECT.CPINFO supported: #CP = false
MaxEnclaveSize_Not64 (log2) = 0x1f (31)
MaxEnclaveSize_64 (log2) = 0x38 (56)
Step 2. Disable SGX in guest

root@KVM-host:# rmmod kvm_intel
root@KVM-host:# modprobe kvm_intel sgx=0
Step 3. The SGX EDECCSSA capability is cleared in KVM, then its status becomes false

[root@guest ~]# cpuid -1 -l 0x12
CPU:
Software Guard Extensions (SGX) capability (0x12/0):
SGX1 supported = false
SGX2 supported = false
SGX ENCLV E*VIRTCHILD, ESETCONTEXT = false
SGX ENCLS ETRACKC, ERDINFO, ELDBC, ELDUC = false
SGX ENCLU EVERIFYREPORT2 = false
SGX ENCLS EUPDATESVN = false
SGX ENCLU EDECCSSA = false
MISCSELECT.EXINFO supported: #PF & #GP = false
MISCSELECT.CPINFO supported: #CP = false
MaxEnclaveSize_Not64 (log2) = 0x0 (0)
MaxEnclaveSize_64 (log2) = 0x0 (0)
[root@TDX-guest ~]#
Known issue:
None

Default config change:
None

Link: https://gitee.com/OpenCloudOS/OpenCloudOS-Kernel/pulls/307

Upstream commit 7efb4d8a392a18e37fcdb5e77c111af6e9a9e2f2 Conflict: none

When SGX EDECCSSA support was added to KVM in commit 16a7fe3 ("KVM/VMX: Allow exposing EDECCSSA user leaf function to KVM guest"), it forgot to clear the X86_FEATURE_SGX_EDECCSSA bit in KVM CPU caps when KVM SGX is disabled. Fix it.

Intel-SIG: commit 7efb4d8a392a KVM: VMX: Also clear SGX EDECCSSA in KVM CPU caps when SGX is disabled
Backport a SGX bug fix from upstream.

Fixes: 16a7fe3 ("KVM/VMX: Allow exposing EDECCSSA user leaf function to KVM guest")

Link: https://lore.kernel.org/r/[email protected]

[ Zhiquan Li: amend commit log ]

Summary by Sourcery

Bug Fixes:

• Clear the X86_FEATURE_SGX_EDECCSSA bit in KVM CPU capabilities when KVM SGX is disabled to resolve an issue where the bit remained set even when SGX was disabled in the guest VM. This fixes a bug introduced when EDECCSSA support was added to KVM, ensuring that the guest CPU capabilities accurately reflect the SGX configuration.

[sourcery-ai]

Reviewer's Guide by Sourcery

This pull request backports a fix that ensures the SGX EDECCSSA capability is correctly cleared in KVM CPU caps when SGX is disabled. This is achieved by adding a kvm_cpu_cap_clear call within the vmx_set_cpu_caps function.

No diagrams generated as the changes look simple and do not need a visual representation.

File-Level Changes

Change	Details	Files
The SGX EDECCSSA capability is now cleared in KVM CPU caps when SGX is disabled.	Added a call to kvm_cpu_cap_clear(X86_FEATURE_SGX_EDECCSSA) within the vmx_set_cpu_caps function when SGX is disabled.	arch/x86/kvm/vmx/vmx.c

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[sourcery-ai]

Hey @Avenger-285714 - I've reviewed your changes - here's some feedback:

Overall Comments:

• The commit message is well-formatted and provides sufficient context for the change.

Here's what I looked at during the review

• 🟢 General issues: all looks good
• 🟢 Security: all looks good
• 🟢 Testing: all looks good
• 🟢 Complexity: all looks good
• 🟢 Documentation: all looks good

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[deepin-ci-robot]

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