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KVM: x86: Use gpa_t for cr2/gpa to fix TDP support on 32-bit KVM

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Convert a plethora of parameters and variables in the MMU and page fault
flows from type gva_t to gpa_t to properly handle TDP on 32-bit KVM.

Thanks to PSE and PAE paging, 32-bit kernels can access 64-bit physical
addresses.  When TDP is enabled, the fault address is a guest physical
address and thus can be a 64-bit value, even when both KVM and its guest
are using 32-bit virtual addressing, e.g. VMX's VMCS.GUEST_PHYSICAL is a
64-bit field, not a natural width field.

Using a gva_t for the fault address means KVM will incorrectly drop the
upper 32-bits of the GPA.  Ditto for gva_to_gpa() when it is used to
translate L2 GPAs to L1 GPAs.

Opportunistically rename variables and parameters to better reflect the
dual address modes, e.g. use "cr2_or_gpa" for fault addresses and plain
"addr" instead of "vaddr" when the address may be either a GVA or an L2
GPA.  Similarly, use "gpa" in the nonpaging_page_fault() flows to avoid
a confusing "gpa_t gva" declaration; this also sets the stage for a
future patch to combing nonpaging_page_fault() and tdp_page_fault() with
minimal churn.

Sprinkle in a few comments to document flows where an address is known
to be a GVA and thus can be safely truncated to a 32-bit value.  Add
WARNs in kvm_handle_page_fault() and FNAME(gva_to_gpa_nested)() to help
document such cases and detect bugs.

Cc: stable@vger.kernel.org
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
This commit is contained in:
Sean Christopherson
2019-12-06 15:57:14 -08:00
committed by Paolo Bonzini
parent 95145c25a7
commit 736c291c9f
8 changed files with 94 additions and 78 deletions
Download Patch File Download Diff File Expand all files Collapse all files

12
arch/x86/kvm/mmutrace.h
View File

@@ -249,13 +249,13 @@ TRACE_EVENT(
TRACE_EVENT(
fast_page_fault,
TP_PROTO(struct kvm_vcpu *vcpu, gva_t gva, u32 error_code,
TP_PROTO(struct kvm_vcpu *vcpu, gpa_t cr2_or_gpa, u32 error_code,
u64 *sptep, u64 old_spte, bool retry),
TP_ARGS(vcpu, gva, error_code, sptep, old_spte, retry),
TP_ARGS(vcpu, cr2_or_gpa, error_code, sptep, old_spte, retry),
TP_STRUCT__entry(
__field(int, vcpu_id)
__field(gva_t, gva)
__field(gpa_t, cr2_or_gpa)
__field(u32, error_code)
__field(u64 *, sptep)
__field(u64, old_spte)
@@ -265,7 +265,7 @@ TRACE_EVENT(
TP_fast_assign(
__entry->vcpu_id = vcpu->vcpu_id;
__entry->gva = gva;
__entry->cr2_or_gpa = cr2_or_gpa;
__entry->error_code = error_code;
__entry->sptep = sptep;
__entry->old_spte = old_spte;
@@ -273,9 +273,9 @@ TRACE_EVENT(
__entry->retry = retry;
),
TP_printk("vcpu %d gva %lx error_code %s sptep %p old %#llx"
TP_printk("vcpu %d gva %llx error_code %s sptep %p old %#llx"
" new %llx spurious %d fixed %d", __entry->vcpu_id,
__entry->gva, __print_flags(__entry->error_code, "|",
__entry->cr2_or_gpa, __print_flags(__entry->error_code, "|",
kvm_mmu_trace_pferr_flags), __entry->sptep,
__entry->old_spte, __entry->new_spte,
__spte_satisfied(old_spte), __spte_satisfied(new_spte)