KVM: x86: Prepare kvm_hv_flush_tlb() to handle L2's GPAs

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@redhat.com>
Reviewed-by: Sean Christopherson <seanjc@google.com>
Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Message-Id: <20221101145426.251680-14-vkuznets@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

diff --git a/arch/x86/kvm/hyperv.c b/arch/x86/kvm/hyperv.c
index fca9c51891f5f6e6b4e55a42a9d21a701bd8bbe6..cb145987f5b854962d7d315a29de30b85dc2a99d 100644 (file)
--- 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) {