Rework tdp_map() and friends to use __virt_pg_map() and drop the custom
EPT code in __tdp_pg_map() and tdp_create_pte(). The EPT code and
__virt_pg_map() are practically identical, the main differences are:
- EPT uses the EPT struct overlay instead of the PTE masks.
- EPT always assumes 4-level EPTs.
To reuse __virt_pg_map(), extend the PTE masks to work with EPT's RWX and
X-only capabilities, and provide a tdp_mmu_init() API so that EPT can pass
in the EPT PTE masks along with the root page level (which is currently
hardcoded to '4').
Don't reuse KVM's insane overloading of the USER bit for EPT_R as there's
no reason to multiplex bits in the selftests, e.g. selftests aren't trying
to shadow guest PTEs and thus don't care about funnelling protections into
a common permissions check.
Another benefit of reusing the code is having separate handling for
upper-level PTEs vs 4K PTEs, which avoids some quirks like setting the
large bit on a 4K PTE in the EPTs.
For all intents and purposes, no functional change intended.
Suggested-by: Sean Christopherson <seanjc@google.com>
Signed-off-by: Yosry Ahmed <yosry.ahmed@linux.dev>
Co-developed-by: Sean Christopherson <seanjc@google.com>
Link: https://patch.msgid.link/20251230230150.4150236-14-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
prepare_eptp() currently allocates new EPTs for each vCPU. memstress has
its own hack to share the EPTs between vCPUs. Currently, there is no
reason to have separate EPTs for each vCPU, and the complexity is
significant. The only reason it doesn't matter now is because memstress
is the only user with multiple vCPUs.
Add vm_enable_ept() to allocate EPT page tables for an entire VM, and use
it everywhere to replace prepare_eptp(). Drop 'eptp' and 'eptp_hva' from
'struct vmx_pages' as they serve no purpose (e.g. the EPTP can be built
from the PGD), but keep 'eptp_gpa' so that the MMU structure doesn't need
to be passed in along with vmx_pages. Dynamically allocate the TDP MMU
structure to avoid a cyclical dependency between kvm_util_arch.h and
kvm_util.h.
Remove the workaround in memstress to copy the EPT root between vCPUs
since that's now the default behavior.
Name the MMU tdp_mmu instead of e.g. nested_mmu or nested.mmu to avoid
recreating the same mess that KVM has with respect to "nested" MMUs, e.g.
does nested refer to the stage-2 page tables created by L1, or the stage-1
page tables created by L2?
Signed-off-by: Yosry Ahmed <yosry.ahmed@linux.dev>
Co-developed-by: Sean Christopherson <seanjc@google.com>
Link: https://patch.msgid.link/20251230230150.4150236-11-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
Move the PTE bitmasks into kvm_mmu to parameterize them for virt mapping
functions. Introduce helpers to read/write different PTE bits given a
kvm_mmu.
Drop the 'global' bit definition as it's currently unused, but leave the
'user' bit as it will be used in coming changes. Opportunisitcally
rename 'large' to 'huge' as it's more consistent with the kernel naming.
Leave PHYSICAL_PAGE_MASK alone, it's fixed in all page table formats and
a lot of other macros depend on it. It's tempting to move all the other
macros to be per-struct instead, but it would be too much noise for
little benefit.
Keep c_bit and s_bit in vm->arch as they used before the MMU is
initialized, through __vmcreate() -> vm_userspace_mem_region_add() ->
vm_mem_add() -> vm_arch_has_protected_memory().
No functional change intended.
Signed-off-by: Yosry Ahmed <yosry.ahmed@linux.dev>
[sean: rename accessors to is_<adjective>_pte()]
Link: https://patch.msgid.link/20251230230150.4150236-10-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
Use the kernel's canonical $(ARCH) paths instead of the raw target triple
for KVM selftests directories. KVM selftests are quite nearly the only
place in the entire kernel that using the target triple for directories,
tools/testing/selftests/drivers/s390x being the lone holdout.
Using the kernel's preferred nomenclature eliminates the minor, but
annoying, friction of having to translate to KVM's selftests directories,
e.g. for pattern matching, opening files, running selftests, etc.
Opportunsitically delete file comments that reference the full path of the
file, as they are obviously prone to becoming stale, and serve no known
purpose.
Reviewed-by: Muhammad Usama Anjum <usama.anjum@collabora.com>
Acked-by: Claudio Imbrenda <imbrenda@linux.ibm.com>
Acked-by: Andrew Jones <ajones@ventanamicro.com>
Link: https://lore.kernel.org/r/20241128005547.4077116-16-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
