Separate the functions for generating MMIO page table entries from the
function that inserts them into the paging structure. This refactoring
will allow changes to the MMU sychronization model to use atomic
compare / exchanges (which are not guaranteed to succeed) instead of a
monolithic MMU lock.
Signed-off-by: Ben Gardon <bgardon@xxxxxxxxxx>
---
arch/x86/kvm/mmu.c | 14 ++++++++++++--
1 file changed, 12 insertions(+), 2 deletions(-)
diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c
index 5269aa057dfa6..781c2ca7455e3 100644
--- a/arch/x86/kvm/mmu.c
+++ b/arch/x86/kvm/mmu.c
@@ -390,8 +390,7 @@ static u64 get_mmio_spte_generation(u64 spte)
return gen;
}
-static void mark_mmio_spte(struct kvm_vcpu *vcpu, u64 *sptep, u64 gfn,
- unsigned access)
+static u64 generate_mmio_pte(struct kvm_vcpu *vcpu, u64 gfn, unsigned access)
{
u64 gen = kvm_vcpu_memslots(vcpu)->generation & MMIO_SPTE_GEN_MASK;
u64 mask = generation_mmio_spte_mask(gen);
@@ -403,6 +402,17 @@ static void mark_mmio_spte(struct kvm_vcpu *vcpu, u64 *sptep, u64 gfn,
mask |= (gpa & shadow_nonpresent_or_rsvd_mask)
<< shadow_nonpresent_or_rsvd_mask_len;
+ return mask;
+}
+
+static void mark_mmio_spte(struct kvm_vcpu *vcpu, u64 *sptep, u64 gfn,
+ unsigned access)
+{
+ u64 mask = generate_mmio_pte(vcpu, gfn, access);
+ unsigned int gen = get_mmio_spte_generation(mask);
+
+ access = mask & ACC_ALL;
+
trace_mark_mmio_spte(sptep, gfn, access, gen);
mmu_spte_set(sptep, mask);
}
--
2.23.0.444.g18eeb5a265-goog
