[PATCH v2 4/8] KVM: x86: Add a helper to get the sparse VP_SET for IPIs and TLB flushes

Sean Christopherson
2021-10-30T00:08:36Z

Add a helper, kvm_get_sparse_vp_set(), to handle sanity checks related to
the VARHEAD field and reading the sparse banks of a VP_SET. A future
commit to reduce the memory footprint of sparse_banks will introduce more
common code to the sparse bank retrieval.

No functional change intended.

Signed-off-by: Sean Christopherson <seanjc@google.com>
---
arch/x86/kvm/hyperv.c | 32 ++++++++++++++++----------------
1 file changed, 16 insertions(+), 16 deletions(-)

diff --git a/arch/x86/kvm/hyperv.c b/arch/x86/kvm/hyperv.c
index e68931ed27f6..3d0981163eed 100644
--- a/arch/x86/kvm/hyperv.c
+++ b/arch/x86/kvm/hyperv.c
@@ -1750,10 +1750,19 @@ struct kvm_hv_hcall {
sse128_t xmm[HV_HYPERCALL_MAX_XMM_REGISTERS];
};

+static u64 kvm_get_sparse_vp_set(struct kvm *kvm, struct kvm_hv_hcall *hc,
+ u64 *sparse_banks, gpa_t offset)
+{
+ if (hc->var_cnt > 64)
+ return -EINVAL;
+
+ return kvm_read_guest(kvm, hc->ingpa + offset, sparse_banks,
+ hc->var_cnt * sizeof(*sparse_banks));
+}
+
static u64 kvm_hv_flush_tlb(struct kvm_vcpu *vcpu, struct kvm_hv_hcall *hc, bool ex)
{
int i;
- gpa_t gpa;
struct kvm *kvm = vcpu->kvm;
struct hv_tlb_flush_ex flush_ex;
struct hv_tlb_flush flush;
@@ -1830,13 +1839,9 @@ static u64 kvm_hv_flush_tlb(struct kvm_vcpu *vcpu, struct kvm_hv_hcall *hc, bool
goto do_flush;
}

- if (hc->var_cnt > 64)
- return HV_STATUS_INVALID_HYPERCALL_INPUT;
-
- gpa = hc->ingpa + offsetof(struct hv_tlb_flush_ex,
- hv_vp_set.bank_contents);
- if (unlikely(kvm_read_guest(kvm, gpa, sparse_banks,
- hc->var_cnt * sizeof(sparse_banks[0]))))
+ if (kvm_get_sparse_vp_set(kvm, hc, sparse_banks,
+ offsetof(struct hv_tlb_flush_ex,
+ hv_vp_set.bank_contents)))
return HV_STATUS_INVALID_HYPERCALL_INPUT;
}

@@ -1933,14 +1938,9 @@ static u64 kvm_hv_send_ipi(struct kvm_vcpu *vcpu, struct kvm_hv_hcall *hc, bool
if (!hc->var_cnt)
goto ret_success;

- if (hc->var_cnt > 64)
- return HV_STATUS_INVALID_HYPERCALL_INPUT;
-
- if (kvm_read_guest(kvm,
- hc->ingpa + offsetof(struct hv_send_ipi_ex,
- vp_set.bank_contents),
- sparse_banks,
- hc->var_cnt * sizeof(sparse_banks[0])))
+ if (kvm_get_sparse_vp_set(kvm, hc, sparse_banks,
+ offsetof(struct hv_send_ipi_ex,
+ vp_set.bank_contents)))
return HV_STATUS_INVALID_HYPERCALL_INPUT;
}

--
2.33.1.1089.g2158813163f-goog