KVM: x86: Gracefully handle __vmalloc() failure during VM allocation

[platform/kernel/linux-rpi.git] / arch / x86 / kvm / svm.c

diff --git a/arch/x86/kvm/svm.c b/arch/x86/kvm/svm.c
index 207030d..51ff6b3 100644 (file)
--- a/arch/x86/kvm/svm.c
+++ b/arch/x86/kvm/svm.c
@@ -1298,6 +1298,47 @@ static void shrink_ple_window(struct kvm_vcpu *vcpu)
        }
 }
 
+/*
+ * The default MMIO mask is a single bit (excluding the present bit),
+ * which could conflict with the memory encryption bit. Check for
+ * memory encryption support and override the default MMIO mask if
+ * memory encryption is enabled.
+ */
+static __init void svm_adjust_mmio_mask(void)
+{
+       unsigned int enc_bit, mask_bit;
+       u64 msr, mask;
+
+       /* If there is no memory encryption support, use existing mask */
+       if (cpuid_eax(0x80000000) < 0x8000001f)
+               return;
+
+       /* If memory encryption is not enabled, use existing mask */
+       rdmsrl(MSR_K8_SYSCFG, msr);
+       if (!(msr & MSR_K8_SYSCFG_MEM_ENCRYPT))
+               return;
+
+       enc_bit = cpuid_ebx(0x8000001f) & 0x3f;
+       mask_bit = boot_cpu_data.x86_phys_bits;
+
+       /* Increment the mask bit if it is the same as the encryption bit */
+       if (enc_bit == mask_bit)
+               mask_bit++;
+
+       /*
+        * If the mask bit location is below 52, then some bits above the
+        * physical addressing limit will always be reserved, so use the
+        * rsvd_bits() function to generate the mask. This mask, along with
+        * the present bit, will be used to generate a page fault with
+        * PFER.RSV = 1.
+        *
+        * If the mask bit location is 52 (or above), then clear the mask.
+        */
+       mask = (mask_bit < 52) ? rsvd_bits(mask_bit, 51) | PT_PRESENT_MASK : 0;
+
+       kvm_mmu_set_mmio_spte_mask(mask, mask, PT_WRITABLE_MASK | PT_USER_MASK);
+}
+
 static __init int svm_hardware_setup(void)
 {
        int cpu;
@@ -1352,6 +1393,8 @@ static __init int svm_hardware_setup(void)
                }
        }
 
+       svm_adjust_mmio_mask();
+
        for_each_possible_cpu(cpu) {
                r = svm_cpu_init(cpu);
                if (r)
@@ -1883,6 +1926,10 @@ static struct kvm *svm_vm_alloc(void)
        struct kvm_svm *kvm_svm = __vmalloc(sizeof(struct kvm_svm),
                                            GFP_KERNEL_ACCOUNT | __GFP_ZERO,
                                            PAGE_KERNEL);
+
+       if (!kvm_svm)
+               return NULL;
+
        return &kvm_svm->kvm;
 }