iv/linux
1
0
Fork 0
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity

KVM: x86/mmu: Return old SPTE from mmu_spte_clear_track_bits()

Browse Source 
Return the old SPTE when clearing a SPTE and push the "old SPTE present"
check to the caller.  Private shadow page support will use the old SPTE
in rmap_remove() to determine whether or not there is a linked private
shadow page.

Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Isaku Yamahata <isaku.yamahata@intel.com>
Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
Message-Id: <b16bac1fd1357aaf39e425aab2177d3f89ee8318.1625186503.git.isaku.yamahata@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
This commit is contained in:
Sean Christopherson 2021-07-02 15:04:51 -07:00 committed by Paolo Bonzini
parent 03fffc5493
commit 7fa2a34751
1 changed files with 7 additions and 5 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

12
arch/x86/kvm/mmu/mmu.c
View File

@ -592,9 +592,9 @@ static bool mmu_spte_update(u64 *sptep, u64 new_spte)
* Rules for using mmu_spte_clear_track_bits:
* It sets the sptep from present to nonpresent, and track the
* state bits, it is used to clear the last level sptep.
* Returns non-zero if the PTE was previously valid.
* Returns the old PTE.
*/
static int mmu_spte_clear_track_bits(u64 *sptep)
static u64 mmu_spte_clear_track_bits(u64 *sptep)
{
kvm_pfn_t pfn;
u64 old_spte = *sptep;
@ -605,7 +605,7 @@ static int mmu_spte_clear_track_bits(u64 *sptep)
old_spte = __update_clear_spte_slow(sptep, 0ull);
if (!is_shadow_present_pte(old_spte))
return 0;
return old_spte;
pfn = spte_to_pfn(old_spte);
@ -622,7 +622,7 @@ static int mmu_spte_clear_track_bits(u64 *sptep)
if (is_dirty_spte(old_spte))
kvm_set_pfn_dirty(pfn);
return 1;
return old_spte;
}
/*
@ -1119,7 +1119,9 @@ out:
static void drop_spte(struct kvm *kvm, u64 *sptep)
{
if (mmu_spte_clear_track_bits(sptep))
u64 old_spte = mmu_spte_clear_track_bits(sptep);
if (is_shadow_present_pte(old_spte))
rmap_remove(kvm, sptep);
}