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Commit 5192f9b9 authored by Sean Christopherson's avatar Sean Christopherson Committed by Paolo Bonzini
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KVM: x86: Use a u64 when passing the MMIO gen around 



KVM currently uses an 'unsigned int' for the MMIO generation number
despite it being derived from the 64-bit memslots generation and
being propagated to (potentially) 64-bit sptes.  There is no hidden
agenda behind using an 'unsigned int', it's done simply because the
MMIO generation will never set bits above bit 19.

Passing a u64 will allow the "update in-progress" flag to be relocated
from bit 0 to bit 63 and removes the need to cast the generation back
to a u64 when propagating it to a spte.

Signed-off-by: default avatarSean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
parent 361209e0

arch/x86/kvm/mmu.c

+7 −7
Original line number Diff line number Diff line
@@ -348,20 +348,20 @@ static inline bool is_access_track_spte(u64 spte) 
#define MMIO_GEN_LOW_MASK		((1 << MMIO_GEN_LOW_SHIFT) - 2)

#define MMIO_GEN_MASK			((1 << MMIO_GEN_SHIFT) - 1)



static u64 generation_mmio_spte_mask(unsigned int gen)

static u64 generation_mmio_spte_mask(u64 gen)

{

	u64 mask;



	WARN_ON(gen & ~MMIO_GEN_MASK);



	mask = (gen & MMIO_GEN_LOW_MASK) << MMIO_SPTE_GEN_LOW_SHIFT;

	mask |= ((u64)gen >> MMIO_GEN_LOW_SHIFT) << MMIO_SPTE_GEN_HIGH_SHIFT;

	mask |= (gen >> MMIO_GEN_LOW_SHIFT) << MMIO_SPTE_GEN_HIGH_SHIFT;

	return mask;

}



static unsigned int get_mmio_spte_generation(u64 spte)

static u64 get_mmio_spte_generation(u64 spte)

{

	unsigned int gen;

	u64 gen;



	spte &= ~shadow_mmio_mask;
@@ -370,7 +370,7 @@ static unsigned int get_mmio_spte_generation(u64 spte) 
	return gen;

}



static unsigned int kvm_current_mmio_generation(struct kvm_vcpu *vcpu)

static u64 kvm_current_mmio_generation(struct kvm_vcpu *vcpu)

{

	return kvm_vcpu_memslots(vcpu)->generation & MMIO_GEN_MASK;

}
@@ -378,7 +378,7 @@ static unsigned int kvm_current_mmio_generation(struct kvm_vcpu *vcpu) 
static void mark_mmio_spte(struct kvm_vcpu *vcpu, u64 *sptep, u64 gfn,

			   unsigned access)

{

	unsigned int gen = kvm_current_mmio_generation(vcpu);

	u64 gen = kvm_current_mmio_generation(vcpu);

	u64 mask = generation_mmio_spte_mask(gen);

	u64 gpa = gfn << PAGE_SHIFT;
@@ -426,7 +426,7 @@ static bool set_mmio_spte(struct kvm_vcpu *vcpu, u64 *sptep, gfn_t gfn, 


static bool check_mmio_spte(struct kvm_vcpu *vcpu, u64 spte)

{

	unsigned int kvm_gen, spte_gen;

	u64 kvm_gen, spte_gen;



	kvm_gen = kvm_current_mmio_generation(vcpu);

	spte_gen = get_mmio_spte_generation(spte);