[Xen-devel] [PATCH 1/4] x86/vvmx: Unconditionally initialise vmxon_region_pa during vcpu construction

[Andrew Cooper <andrew.cooper3@xxxxxxxxxx>]

This is a stopgap solution until the toolstack side of initialisation can be
sorted out, but it does result in the nvmx_vcpu_in_vmx() predicate working
correctly even when nested virt hasn't been enabled for the domain.

Update nvmx_handle_vmx_insn() to include the in-vmx mode check (for all
instructions other than VMXON) to complete the set of #UD checks.

In addition, sanity check that the nested vmexit handler has worked correctly,
and that we are only providing emulation of the VT-x instructions to L1
guests.

Signed-off-by: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
---
CC: Sergey Dyasli <sergey.dyasli@xxxxxxxxxx>
CC: Jan Beulich <JBeulich@xxxxxxxx>
CC: Wei Liu <wei.liu2@xxxxxxxxxx>
CC: Jun Nakajima <jun.nakajima@xxxxxxxxx>
CC: Kevin Tian <kevin.tian@xxxxxxxxx>
---
 xen/arch/x86/hvm/vmx/vmx.c  |  2 ++
 xen/arch/x86/hvm/vmx/vvmx.c | 11 ++++++++++-
 2 files changed, 12 insertions(+), 1 deletion(-)

diff --git a/xen/arch/x86/hvm/vmx/vmx.c b/xen/arch/x86/hvm/vmx/vmx.c
index 7a49075..00a7014 100644
--- a/xen/arch/x86/hvm/vmx/vmx.c
+++ b/xen/arch/x86/hvm/vmx/vmx.c
@@ -429,6 +429,8 @@ static int vmx_vcpu_initialise(struct vcpu *v)
 
     INIT_LIST_HEAD(&v->arch.hvm.vmx.pi_blocking.list);
 
+    vcpu_2_nvmx(v).vmxon_region_pa = INVALID_PADDR;
+
     if ( (rc = vmx_create_vmcs(v)) != 0 )
     {
         dprintk(XENLOG_WARNING,
diff --git a/xen/arch/x86/hvm/vmx/vvmx.c b/xen/arch/x86/hvm/vmx/vvmx.c
index aa202e0..09e105e 100644
--- a/xen/arch/x86/hvm/vmx/vvmx.c
+++ b/xen/arch/x86/hvm/vmx/vvmx.c
@@ -1987,7 +1987,8 @@ int nvmx_handle_vmx_insn(struct cpu_user_regs *regs, 
unsigned int exit_reason)
 
     if ( !(curr->arch.hvm.guest_cr[4] & X86_CR4_VMXE) ||
          !nestedhvm_enabled(curr->domain) ||
-         (vmx_guest_x86_mode(curr) < (hvm_long_mode_active(curr) ? 8 : 2)) )
+         (vmx_guest_x86_mode(curr) < (hvm_long_mode_active(curr) ? 8 : 2)) ||
+         (exit_reason != EXIT_REASON_VMXON && !nvmx_vcpu_in_vmx(curr)) )
     {
         hvm_inject_hw_exception(TRAP_invalid_op, X86_EVENT_NO_EC);
         return X86EMUL_EXCEPTION;
@@ -1999,6 +2000,14 @@ int nvmx_handle_vmx_insn(struct cpu_user_regs *regs, 
unsigned int exit_reason)
         return X86EMUL_EXCEPTION;
     }
 
+    if ( nestedhvm_vcpu_in_guestmode(curr) )
+    {
+        /* Should have been handled by nvmx_n2_vmexit_handler()... */
+        ASSERT_UNREACHABLE();
+        domain_crash(curr->domain);
+        return X86EMUL_UNHANDLEABLE;
+    }
+
     switch ( exit_reason )
     {
     case EXIT_REASON_VMXOFF:
-- 
2.1.4


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