Commit c3521485 authored by Sean Christopherson's avatar Sean Christopherson Committed by Yu Zhang
Browse files

KVM: x86/mmu: Use boolean returns for (S)PTE accessors 

mainline inclusion
from mainline-v5.12-rc1
commit 15e6a7e5
category: feature
bugzilla: https://gitee.com/openeuler/intel-kernel/issues/I7S3VQ
CVE: NA

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=15e6a7e5324cc04a67891fc369ea834bbb7e7b42



----------------------------------------------------------------------

Return a 'bool' instead of an 'int' for various PTE accessors that are
boolean in nature, e.g. is_shadow_present_pte().  Returning an int is
goofy and potentially dangerous, e.g. if a flag being checked is moved
into the upper 32 bits of a SPTE, then the compiler may silently squash
the entire check since casting to an int is guaranteed to yield a
return value of '0'.

Opportunistically refactor is_last_spte() so that it naturally returns
a bool value instead of letting it implicitly cast 0/1 to false/true.

No functional change intended.

Signed-off-by: default avatarSean Christopherson <seanjc@google.com>
Message-Id: <20210123003003.3137525-1-seanjc@google.com>
Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
Signed-off-by: default avatarYu Zhang <yu.c.zhang@linux.intel.com>
parent b8d20195

arch/x86/kvm/mmu.h

+1 −1
Original line number Diff line number Diff line
@@ -145,7 +145,7 @@ static inline int kvm_mmu_do_page_fault(struct kvm_vcpu *vcpu, gpa_t cr2_or_gpa, 
 *

 * TODO: introduce APIs to split these two cases.

 */

static inline int is_writable_pte(unsigned long pte)

static inline bool is_writable_pte(unsigned long pte)

{

	return pte & PT_WRITABLE_MASK;

}

arch/x86/kvm/mmu/spte.h

+4 −8
Original line number Diff line number Diff line
@@ -179,23 +179,19 @@ static inline bool is_access_track_spte(u64 spte) 
	return !spte_ad_enabled(spte) && (spte & shadow_acc_track_mask) == 0;

}



static inline int is_shadow_present_pte(u64 pte)

static inline bool is_shadow_present_pte(u64 pte)

{

	return (pte != 0) && !is_mmio_spte(pte);

}



static inline int is_large_pte(u64 pte)

static inline bool is_large_pte(u64 pte)

{

	return pte & PT_PAGE_SIZE_MASK;

}



static inline int is_last_spte(u64 pte, int level)

static inline bool is_last_spte(u64 pte, int level)

{

	if (level == PG_LEVEL_4K)

		return 1;

	if (is_large_pte(pte))

		return 1;

	return 0;

	return (level == PG_LEVEL_4K) || is_large_pte(pte);

}



static inline bool is_executable_pte(u64 spte)