Please pull a handful of fixes for 6.14. The DEBUGCTL changes are the most urgent, as they fix a bug that was introduced in 6.13 that results in Steam (and other applications) getting killed due to unexpected #DBs. The following changes since commit c2fee09fc167c74a64adb08656cb993ea475197e: KVM: x86: Load DR6 with guest value only before entering .vcpu_run() loop (2025-02-12 08:59:38 -0800) are available in the Git repository at: https://github.com/kvm-x86/linux.git tags/kvm-x86-fixes-6.14-rcN.2 for you to fetch changes up to f9dc8fb3afc968042bdaf4b6e445a9272071c9f3: KVM: x86: Explicitly zero EAX and EBX when PERFMON_V2 isn't supported by KVM (2025-03-04 09:19:18 -0800) ---------------------------------------------------------------- KVM x86 fixes for 6.14-rcN #2 - Set RFLAGS.IF in C code on SVM to get VMRUN out of the STI shadow. - Ensure DEBUGCTL is context switched on AMD to avoid running the guest with the host's value, which can lead to unexpected bus lock #DBs. - Suppress DEBUGCTL.BTF on AMD (to match Intel), as KVM doesn't properly emulate BTF. KVM's lack of context switching has meant BTF has always been broken to some extent. - Always save DR masks for SNP vCPUs if DebugSwap is *supported*, as the guest can enable DebugSwap without KVM's knowledge. - Fix a bug in mmu_stress_tests where a vCPU could finish the "writes to RO memory" phase without actually generating a write-protection fault. - Fix a printf() goof in the SEV smoke test that causes build failures with -Werror. - Explicitly zero EAX and EBX in CPUID.0x8000_0022 output when PERFMON_V2 isn't supported by KVM. ---------------------------------------------------------------- Sean Christopherson (11): KVM: SVM: Set RFLAGS.IF=1 in C code, to get VMRUN out of the STI shadow KVM: selftests: Assert that STI blocking isn't set after event injection KVM: SVM: Drop DEBUGCTL[5:2] from guest's effective value KVM: SVM: Suppress DEBUGCTL.BTF on AMD KVM: x86: Snapshot the host's DEBUGCTL in common x86 KVM: SVM: Manually context switch DEBUGCTL if LBR virtualization is disabled KVM: x86: Snapshot the host's DEBUGCTL after disabling IRQs KVM: SVM: Save host DR masks on CPUs with DebugSwap KVM: SVM: Don't rely on DebugSwap to restore host DR0..DR3 KVM: selftests: Ensure all vCPUs hit -EFAULT during initial RO stage KVM: selftests: Fix printf() format goof in SEV smoke test Xiaoyao Li (1): KVM: x86: Explicitly zero EAX and EBX when PERFMON_V2 isn't supported by KVM arch/x86/include/asm/kvm_host.h | 1 + arch/x86/kvm/cpuid.c | 2 +- arch/x86/kvm/svm/sev.c | 24 +++++++---- arch/x86/kvm/svm/svm.c | 49 ++++++++++++++++++++++ arch/x86/kvm/svm/svm.h | 2 +- arch/x86/kvm/svm/vmenter.S | 10 +---- arch/x86/kvm/vmx/vmx.c | 8 +--- arch/x86/kvm/vmx/vmx.h | 2 - arch/x86/kvm/x86.c | 2 + tools/testing/selftests/kvm/mmu_stress_test.c | 21 ++++++---- .../selftests/kvm/x86/nested_exceptions_test.c | 2 + tools/testing/selftests/kvm/x86/sev_smoke_test.c | 3 +- 12 files changed, 91 insertions(+), 35 deletions(-)
