KVM: x86: dump_vmcs should not assume GUEST_IA32_EFER is valid

If the VM entry/exit controls for loading/saving MSR_EFER are either
not available (an older processor or explicitly disabled) or not
used (host and guest values are the same), reading GUEST_IA32_EFER
from the VMCS returns an inaccurate value.

Because of this, in dump_vmcs() don't use GUEST_IA32_EFER to decide
whether to print the PDPTRs - always do so if the fields exist.

Fixes: 4eb64dce8d0a ("KVM: x86: dump VMCS on invalid entry")
Signed-off-by: David Edmondson <david.edmondson@oracle.com>
Message-Id: <20210318120841.133123-2-david.edmondson@oracle.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c
index 5ab2537..0c39a8e 100644 (file)
--- a/arch/x86/kvm/vmx/vmx.c
+++ b/arch/x86/kvm/vmx/vmx.c
@@ -5726,7 +5726,6 @@ void dump_vmcs(void)
        u32 vmentry_ctl, vmexit_ctl;
        u32 cpu_based_exec_ctrl, pin_based_exec_ctrl, secondary_exec_control;
        unsigned long cr4;
-       u64 efer;
 
        if (!dump_invalid_vmcs) {
                pr_warn_ratelimited("set kvm_intel.dump_invalid_vmcs=1 to dump internal KVM state.\n");
@@ -5738,7 +5737,6 @@ void dump_vmcs(void)
        cpu_based_exec_ctrl = vmcs_read32(CPU_BASED_VM_EXEC_CONTROL);
        pin_based_exec_ctrl = vmcs_read32(PIN_BASED_VM_EXEC_CONTROL);
        cr4 = vmcs_readl(GUEST_CR4);
-       efer = vmcs_read64(GUEST_IA32_EFER);
        secondary_exec_control = 0;
        if (cpu_has_secondary_exec_ctrls())
                secondary_exec_control = vmcs_read32(SECONDARY_VM_EXEC_CONTROL);
@@ -5750,9 +5748,7 @@ void dump_vmcs(void)
        pr_err("CR4: actual=0x%016lx, shadow=0x%016lx, gh_mask=%016lx\n",
               cr4, vmcs_readl(CR4_READ_SHADOW), vmcs_readl(CR4_GUEST_HOST_MASK));
        pr_err("CR3 = 0x%016lx\n", vmcs_readl(GUEST_CR3));
-       if ((secondary_exec_control & SECONDARY_EXEC_ENABLE_EPT) &&
-           (cr4 & X86_CR4_PAE) && !(efer & EFER_LMA))
-       {
+       if (cpu_has_vmx_ept()) {
                pr_err("PDPTR0 = 0x%016llx  PDPTR1 = 0x%016llx\n",
                       vmcs_read64(GUEST_PDPTR0), vmcs_read64(GUEST_PDPTR1));
                pr_err("PDPTR2 = 0x%016llx  PDPTR3 = 0x%016llx\n",
@@ -5778,7 +5774,8 @@ void dump_vmcs(void)
        if ((vmexit_ctl & (VM_EXIT_SAVE_IA32_PAT | VM_EXIT_SAVE_IA32_EFER)) ||
            (vmentry_ctl & (VM_ENTRY_LOAD_IA32_PAT | VM_ENTRY_LOAD_IA32_EFER)))
                pr_err("EFER =     0x%016llx  PAT = 0x%016llx\n",
-                      efer, vmcs_read64(GUEST_IA32_PAT));
+                      vmcs_read64(GUEST_IA32_EFER),
+                      vmcs_read64(GUEST_IA32_PAT));
        pr_err("DebugCtl = 0x%016llx  DebugExceptions = 0x%016lx\n",
               vmcs_read64(GUEST_IA32_DEBUGCTL),
               vmcs_readl(GUEST_PENDING_DBG_EXCEPTIONS));