diff mbox series

[3/3] kvm/svm: limit guest_phys_bits to 48 in 4-level paging mode

Message ID 20240301101410.356007-4-kraxel@redhat.com (mailing list archive)
State New, archived
Headers show
Series kvm: add support for KVM_CAP_VM_GPA_BITS | expand

Commit Message

Gerd Hoffmann March 1, 2024, 10:14 a.m. UTC 
If the host runs in 4-level paging mode NPT is restricted to 4 paging
levels too.  Adjust kvm_caps.guest_phys_bits accordingly.

Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
---
 arch/x86/kvm/svm/svm.c | 5 +++++
 1 file changed, 5 insertions(+)
diff mbox series

Patch

diff --git a/arch/x86/kvm/svm/svm.c b/arch/x86/kvm/svm/svm.c
index e90b429c84f1..8c3e2e3bd468 100644
--- a/arch/x86/kvm/svm/svm.c
+++ b/arch/x86/kvm/svm/svm.c
@@ -5229,6 +5229,11 @@  static __init int svm_hardware_setup(void)
 			  get_npt_level(), PG_LEVEL_1G);
 	pr_info("Nested Paging %sabled\n", npt_enabled ? "en" : "dis");
 
+	if (npt_enabled &&
+	    get_npt_level() == PT64_ROOT_4LEVEL &&
+	    kvm_caps.guest_phys_bits > 48)
+		kvm_caps.guest_phys_bits = 48;
+
 	/* Setup shadow_me_value and shadow_me_mask */
 	kvm_mmu_set_me_spte_mask(sme_me_mask, sme_me_mask);