[PATCH v4 1/5] KVM: x86: dump_vmcs should not assume GUEST_IA32_EFER is valid

From: David Edmondson <david.edmondson@oracle.com>
To: linux-kernel@vger.kernel.org
Cc: Jim Mattson <jmattson@google.com>, Borislav Petkov <bp@alien8.de>,
	Joerg Roedel <joro@8bytes.org>,
	Vitaly Kuznetsov <vkuznets@redhat.com>,
	kvm@vger.kernel.org, Wanpeng Li <wanpengli@tencent.com>,
	Thomas Gleixner <tglx@linutronix.de>,
	Sean Christopherson <seanjc@google.com>,
	Paolo Bonzini <pbonzini@redhat.com>,
	"H. Peter Anvin" <hpa@zytor.com>, Ingo Molnar <mingo@redhat.com>,
	x86@kernel.org, David Edmondson <david.edmondson@oracle.com>
Subject: [PATCH v4 1/5] KVM: x86: dump_vmcs should not assume GUEST_IA32_EFER is valid
Date: Wed, 24 Feb 2021 14:04:52 +0000	[thread overview]
Message-ID: <20210224140456.2558033-2-david.edmondson@oracle.com> (raw)
In-Reply-To: <20210224140456.2558033-1-david.edmondson@oracle.com>

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>

if valid
---
 arch/x86/kvm/vmx/vmx.c | 9 +++------
 1 file changed, 3 insertions(+), 6 deletions(-)

diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c
index e0a3a9be654b..ea1b3a671d51 100644
--- a/arch/x86/kvm/vmx/vmx.c
+++ b/arch/x86/kvm/vmx/vmx.c
@@ -5815,7 +5815,6 @@ 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");
@@ -5827,7 +5826,6 @@ 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);
@@ -5839,9 +5837,7 @@ 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",
@@ -5867,7 +5863,8 @@ 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));
-- 
2.30.0

