Clean up KVM's MSR interception code (especially the SVM code, which is all
kinds of ugly). The main goals are to:
- Make the SVM and VMX APIs consistent (and sane; the current SVM APIs have
inverted polarity).
- Eliminate the shadow bitmaps that are used to determine intercepts on
userspace MSR filter update.
v2:
- Add a patch to set MSR_IA32_SPEC_CTRL interception as appropriate. [Chao]
- Add a patch to cleanup {svm,vmx}_disable_intercept_for_msr() once the
dust has settled. [Dapeng]
- Return -ENOSPC if msrpm_offsets[] is full. [Chao]
- Free iopm_pages directly instead of bouncing through iopm_base. [Chao]
- Check for "offset == MSR_INVALID" before using offset. [Chao]
- Temporarily keep MSR_IA32_DEBUGCTLMSR in the nested list. [Chao]
- Add a comment to explain nested_svm_msrpm_merge_offsets. [Chao]
- Add a patch to shift the IOPM allocation to avoid having to unwind it.
- Init nested_svm_msrpm_merge_offsets iff nested=1. [Chao]
- Add a helper to dedup alloc+init of MSRPM and IOPM.
- Tag merge_msrs as "static" and "__initconst". [Paolo]
- Rework helpers to use fewer macros. [Paolo]
- Account for each MSRPM byte covering 4 MSRs. [Paolo]
- Opportunistically use cpu_feature_enabled(). [Xin]
- Fully remove MAX_DIRECT_ACCESS_MSRS, MSRPM_OFFSETS, and msrpm_offsets.
[Francesco]
- Fix typos. [Dapeng, Chao]
- Collect reviews. [Chao, Dapeng, Xin]
v1: https://lore.kernel.org/all/20250529234013.3826933-1-seanjc@xxxxxxxxxx
v0: https://lore.kernel.org/kvm/20241127201929.4005605-1-aaronlewis@xxxxxxxxxx
Sean Christopherson (32):
KVM: SVM: Disable interception of SPEC_CTRL iff the MSR exists for the
guest
KVM: SVM: Allocate IOPM pages after initial setup in
svm_hardware_setup()
KVM: SVM: Don't BUG if setting up the MSR intercept bitmaps fails
KVM: SVM: Tag MSR bitmap initialization helpers with __init
KVM: SVM: Use ARRAY_SIZE() to iterate over direct_access_msrs
KVM: SVM: Kill the VM instead of the host if MSR interception is buggy
KVM: x86: Use non-atomic bit ops to manipulate "shadow" MSR intercepts
KVM: SVM: Massage name and param of helper that merges vmcb01 and
vmcb12 MSRPMs
KVM: SVM: Clean up macros related to architectural MSRPM definitions
KVM: nSVM: Use dedicated array of MSRPM offsets to merge L0 and L1
bitmaps
KVM: nSVM: Omit SEV-ES specific passthrough MSRs from L0+L1 bitmap
merge
KVM: nSVM: Don't initialize vmcb02 MSRPM with vmcb01's "always
passthrough"
KVM: SVM: Add helpers for accessing MSR bitmap that don't rely on
offsets
KVM: SVM: Implement and adopt VMX style MSR intercepts APIs
KVM: SVM: Pass through GHCB MSR if and only if VM is an SEV-ES guest
KVM: SVM: Drop "always" flag from list of possible passthrough MSRs
KVM: x86: Move definition of X2APIC_MSR() to lapic.h
KVM: VMX: Manually recalc all MSR intercepts on userspace MSR filter
change
KVM: SVM: Manually recalc all MSR intercepts on userspace MSR filter
change
KVM: x86: Rename msr_filter_changed() => recalc_msr_intercepts()
KVM: SVM: Rename init_vmcb_after_set_cpuid() to make it intercepts
specific
KVM: SVM: Fold svm_vcpu_init_msrpm() into its sole caller
KVM: SVM: Merge "after set CPUID" intercept recalc helpers
KVM: SVM: Drop explicit check on MSRPM offset when emulating SEV-ES
accesses
KVM: SVM: Move svm_msrpm_offset() to nested.c
KVM: SVM: Store MSRPM pointer as "void *" instead of "u32 *"
KVM: nSVM: Access MSRPM in 4-byte chunks only for merging L0 and L1
bitmaps
KVM: SVM: Return -EINVAL instead of MSR_INVALID to signal out-of-range
MSR
KVM: nSVM: Merge MSRPM in 64-bit chunks on 64-bit kernels
KVM: SVM: Add a helper to allocate and initialize permissions bitmaps
KVM: x86: Simplify userspace filter logic when disabling MSR
interception
KVM: selftests: Verify KVM disable interception (for userspace) on
filter change
arch/x86/include/asm/kvm-x86-ops.h | 2 +-
arch/x86/include/asm/kvm_host.h | 2 +-
arch/x86/kvm/lapic.h | 2 +
arch/x86/kvm/svm/nested.c | 126 +++--
arch/x86/kvm/svm/sev.c | 29 +-
arch/x86/kvm/svm/svm.c | 490 ++++++------------
arch/x86/kvm/svm/svm.h | 102 +++-
arch/x86/kvm/vmx/main.c | 6 +-
arch/x86/kvm/vmx/vmx.c | 202 ++------
arch/x86/kvm/vmx/vmx.h | 9 -
arch/x86/kvm/vmx/x86_ops.h | 2 +-
arch/x86/kvm/x86.c | 8 +-
.../kvm/x86/userspace_msr_exit_test.c | 8 +
13 files changed, 426 insertions(+), 562 deletions(-)
base-commit: 61374cc145f4a56377eaf87c7409a97ec7a34041
--
2.50.0.rc0.642.g800a2b2222-goog
