[PATCH v13 13/48] KVM: x86: Prepare kvm_hv_flush_tlb() to handle L2's GPAs

[Vitaly Kuznetsov]

To handle L2 TLB flush requests, KVM needs to translate the specified
L2 GPA to L1 GPA to read hypercall arguments from there.

No functional change as KVM doesn't handle VMCALL/VMMCALL from L2 yet.

Reviewed-by: Maxim Levitsky <mlevitsk@xxxxxxxxxx>
Reviewed-by: Sean Christopherson <seanjc@xxxxxxxxxx>
Signed-off-by: Vitaly Kuznetsov <vkuznets@xxxxxxxxxx>
---
 arch/x86/kvm/hyperv.c | 14 ++++++++++++++
 1 file changed, 14 insertions(+)

diff --git a/arch/x86/kvm/hyperv.c b/arch/x86/kvm/hyperv.c
index fca9c51891f5..cb145987f5b8 100644
--- a/arch/x86/kvm/hyperv.c
+++ b/arch/x86/kvm/hyperv.c
@@ -23,6 +23,7 @@
 #include "ioapic.h"
 #include "cpuid.h"
 #include "hyperv.h"
+#include "mmu.h"
 #include "xen.h"
 
 #include <linux/cpu.h>
@@ -1908,6 +1909,19 @@ static u64 kvm_hv_flush_tlb(struct kvm_vcpu *vcpu, struct kvm_hv_hcall *hc)
 	 */
 	BUILD_BUG_ON(KVM_HV_MAX_SPARSE_VCPU_SET_BITS > 64);
 
+	/*
+	 * 'Slow' hypercall's first parameter is the address in guest's memory
+	 * where hypercall parameters are placed. This is either a GPA or a
+	 * nested GPA when KVM is handling the call from L2 ('direct' TLB
+	 * flush).  Translate the address here so the memory can be uniformly
+	 * read with kvm_read_guest().
+	 */
+	if (!hc->fast && is_guest_mode(vcpu)) {
+		hc->ingpa = translate_nested_gpa(vcpu, hc->ingpa, 0, NULL);
+		if (unlikely(hc->ingpa == INVALID_GPA))
+			return HV_STATUS_INVALID_HYPERCALL_INPUT;
+	}
+
 	if (hc->code == HVCALL_FLUSH_VIRTUAL_ADDRESS_LIST ||
 	    hc->code == HVCALL_FLUSH_VIRTUAL_ADDRESS_SPACE) {
 		if (hc->fast) {
-- 
2.37.3