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KVM: x86/mmu: Avoid mixing gpa_t with gfn_t in walk_addr_generic() 

translate_gpa() returns a GPA, assigning it to 'real_gfn' seems obviously
wrong. There is no real issue because both 'gpa_t' and 'gfn_t' are u64 and
we don't use the value in 'real_gfn' as a GFN, we do

 real_gfn = gpa_to_gfn(real_gfn);

instead. 'If you see a "buffalo" sign on an elephant's cage, do not trust
your eyes', but let's fix it for good.

No functional change intended.

Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Message-Id: <20200622151435.752560-1-vkuznets@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
This commit is contained in:
Vitaly Kuznetsov 2020-06-22 17:14:35 +02:00 committed by Paolo Bonzini
parent 44d5271707
commit 312d16c7c0
1 changed files with 3 additions and 6 deletions
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9
arch/x86/kvm/mmu/paging_tmpl.h
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@ -360,7 +360,6 @@ static int FNAME(walk_addr_generic)(struct guest_walker *walker,
++walker->level;
do {
gfn_t real_gfn;
unsigned long host_addr;
pt_access = pte_access;
@ -375,7 +374,7 @@ static int FNAME(walk_addr_generic)(struct guest_walker *walker,
walker->table_gfn[walker->level - 1] = table_gfn;
walker->pte_gpa[walker->level - 1] = pte_gpa;
real_gfn = mmu->translate_gpa(vcpu, gfn_to_gpa(table_gfn),
real_gpa = mmu->translate_gpa(vcpu, gfn_to_gpa(table_gfn),
nested_access,
&walker->fault);
@ -389,12 +388,10 @@ static int FNAME(walk_addr_generic)(struct guest_walker *walker,
* information to fix the exit_qualification or exit_info_1
* fields.
*/
if (unlikely(real_gfn == UNMAPPED_GVA))
if (unlikely(real_gpa == UNMAPPED_GVA))
return 0;
real_gfn = gpa_to_gfn(real_gfn);
host_addr = kvm_vcpu_gfn_to_hva_prot(vcpu, real_gfn,
host_addr = kvm_vcpu_gfn_to_hva_prot(vcpu, gpa_to_gfn(real_gpa),
&walker->pte_writable[walker->level - 1]);
if (unlikely(kvm_is_error_hva(host_addr)))
goto error;