KVM: Allow cross page reads and writes from cached translations.
This patch adds support for kvm_gfn_to_hva_cache_init functions for
reads and writes that will cross a page. If the range falls within
the same memslot, then this will be a fast operation. If the range
is split between two memslots, then the slower kvm_read_guest and
kvm_write_guest are used.
Tested: Test against kvm_clock unit tests.
Signed-off-by: Andrew Honig <ahonig@google.com>
Signed-off-by: Gleb Natapov <gleb@redhat.com>
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index f19ac0a..e172132 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -1823,7 +1823,8 @@
return 0;
}
- if (kvm_gfn_to_hva_cache_init(vcpu->kvm, &vcpu->arch.apf.data, gpa))
+ if (kvm_gfn_to_hva_cache_init(vcpu->kvm, &vcpu->arch.apf.data, gpa,
+ sizeof(u32)))
return 1;
vcpu->arch.apf.send_user_only = !(data & KVM_ASYNC_PF_SEND_ALWAYS);
@@ -1952,12 +1953,9 @@
gpa_offset = data & ~(PAGE_MASK | 1);
- /* Check that the address is 32-byte aligned. */
- if (gpa_offset & (sizeof(struct pvclock_vcpu_time_info) - 1))
- break;
-
if (kvm_gfn_to_hva_cache_init(vcpu->kvm,
- &vcpu->arch.pv_time, data & ~1ULL))
+ &vcpu->arch.pv_time, data & ~1ULL,
+ sizeof(struct pvclock_vcpu_time_info)))
vcpu->arch.pv_time_enabled = false;
else
vcpu->arch.pv_time_enabled = true;
@@ -1977,7 +1975,8 @@
return 1;
if (kvm_gfn_to_hva_cache_init(vcpu->kvm, &vcpu->arch.st.stime,
- data & KVM_STEAL_VALID_BITS))
+ data & KVM_STEAL_VALID_BITS,
+ sizeof(struct kvm_steal_time)))
return 1;
vcpu->arch.st.msr_val = data;