diff options
| author | Sean Christopherson <seanjc@google.com> | 2021-02-25 12:47:36 -0800 |
|---|---|---|
| committer | Paolo Bonzini <pbonzini@redhat.com> | 2021-03-15 04:43:42 -0400 |
| commit | b09763da4dd8434171c63b32e0b89cf3d689f4b9 (patch) | |
| tree | c09dc8c2e318e64aca42e80ec82824aa02f7eb22 /arch/x86/kvm/mmu | |
| parent | 8120337a4c5502118e255b170799040eefe2f280 (diff) | |
| download | linux-b09763da4dd8434171c63b32e0b89cf3d689f4b9.tar.gz | |
KVM: x86/mmu: Add module param to disable MMIO caching (for testing)
Add a module param to disable MMIO caching so that it's possible to test
the related flows without access to the necessary hardware. Using shadow
paging with 64-bit KVM and 52 bits of physical address space must disable
MMIO caching as there are no reserved bits to be had.
Signed-off-by: Sean Christopherson <seanjc@google.com>
Message-Id: <20210225204749.1512652-12-seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Diffstat (limited to 'arch/x86/kvm/mmu')
| -rw-r--r-- | arch/x86/kvm/mmu/spte.c | 6 |
1 files changed, 6 insertions, 0 deletions
diff --git a/arch/x86/kvm/mmu/spte.c b/arch/x86/kvm/mmu/spte.c index b2379094a8c1..503dec3f8c7a 100644 --- a/arch/x86/kvm/mmu/spte.c +++ b/arch/x86/kvm/mmu/spte.c @@ -17,6 +17,9 @@ #include <asm/e820/api.h> +static bool __read_mostly enable_mmio_caching = true; +module_param_named(mmio_caching, enable_mmio_caching, bool, 0444); + u64 __read_mostly shadow_nx_mask; u64 __read_mostly shadow_x_mask; /* mutual exclusive with nx_mask */ u64 __read_mostly shadow_user_mask; @@ -251,6 +254,9 @@ void kvm_mmu_set_mmio_spte_mask(u64 mmio_value, u64 mmio_mask, u64 access_mask) BUG_ON((u64)(unsigned)access_mask != access_mask); WARN_ON(mmio_value & shadow_nonpresent_or_rsvd_lower_gfn_mask); + if (!enable_mmio_caching) + mmio_value = 0; + /* * Disable MMIO caching if the MMIO value collides with the bits that * are used to hold the relocated GFN when the L1TF mitigation is |