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authorSuthikulpanit, Suravee <Suravee.Suthikulpanit@amd.com>2019-01-29 08:08:42 +0000
committerPaolo Bonzini <pbonzini@redhat.com>2019-02-20 22:48:20 +0100
commit98d90582be2e08246a70af31e09950ecb8876252 (patch)
tree7ef1a56056807cb8653d52c26bb0f91d59619d86
parent90952cd388595317170ad22a6bcee3cb8cde4942 (diff)
svm: Fix AVIC DFR and LDR handling
Current SVM AVIC driver makes two incorrect assumptions: 1. APIC LDR register cannot be zero 2. APIC DFR for all vCPUs must be the same LDR=0 means the local APIC does not support logical destination mode. Therefore, the driver should mark any previously assigned logical APIC ID table entry as invalid, and return success. Also, DFR is specific to a particular local APIC, and can be different among all vCPUs (as observed on Windows 10). These incorrect assumptions cause Windows 10 and FreeBSD VMs to fail to boot with AVIC enabled. So, instead of flush the whole logical APIC ID table, handle DFR and LDR for each vCPU independently. Fixes: 18f40c53e10f ('svm: Add VMEXIT handlers for AVIC') Cc: Radim Krčmář <rkrcmar@redhat.com> Cc: Paolo Bonzini <pbonzini@redhat.com> Reported-by: Julian Stecklina <jsteckli@amazon.de> Signed-off-by: Suravee Suthikulpanit <suravee.suthikulpanit@amd.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
-rw-r--r--arch/x86/kvm/svm.c64
1 files changed, 30 insertions, 34 deletions
diff --git a/arch/x86/kvm/svm.c b/arch/x86/kvm/svm.c
index f13a3a24d360..01b66bbcdd7a 100644
--- a/arch/x86/kvm/svm.c
+++ b/arch/x86/kvm/svm.c
@@ -145,7 +145,6 @@ struct kvm_svm {
/* Struct members for AVIC */
u32 avic_vm_id;
- u32 ldr_mode;
struct page *avic_logical_id_table_page;
struct page *avic_physical_id_table_page;
struct hlist_node hnode;
@@ -236,6 +235,7 @@ struct vcpu_svm {
bool nrips_enabled : 1;
u32 ldr_reg;
+ u32 dfr_reg;
struct page *avic_backing_page;
u64 *avic_physical_id_cache;
bool avic_is_running;
@@ -2106,6 +2106,7 @@ static int avic_init_vcpu(struct vcpu_svm *svm)
INIT_LIST_HEAD(&svm->ir_list);
spin_lock_init(&svm->ir_list_lock);
+ svm->dfr_reg = APIC_DFR_FLAT;
return ret;
}
@@ -4565,8 +4566,7 @@ static u32 *avic_get_logical_id_entry(struct kvm_vcpu *vcpu, u32 ldr, bool flat)
return &logical_apic_id_table[index];
}
-static int avic_ldr_write(struct kvm_vcpu *vcpu, u8 g_physical_id, u32 ldr,
- bool valid)
+static int avic_ldr_write(struct kvm_vcpu *vcpu, u8 g_physical_id, u32 ldr)
{
bool flat;
u32 *entry, new_entry;
@@ -4579,31 +4579,39 @@ static int avic_ldr_write(struct kvm_vcpu *vcpu, u8 g_physical_id, u32 ldr,
new_entry = READ_ONCE(*entry);
new_entry &= ~AVIC_LOGICAL_ID_ENTRY_GUEST_PHYSICAL_ID_MASK;
new_entry |= (g_physical_id & AVIC_LOGICAL_ID_ENTRY_GUEST_PHYSICAL_ID_MASK);
- if (valid)
- new_entry |= AVIC_LOGICAL_ID_ENTRY_VALID_MASK;
- else
- new_entry &= ~AVIC_LOGICAL_ID_ENTRY_VALID_MASK;
+ new_entry |= AVIC_LOGICAL_ID_ENTRY_VALID_MASK;
WRITE_ONCE(*entry, new_entry);
return 0;
}
+static void avic_invalidate_logical_id_entry(struct kvm_vcpu *vcpu)
+{
+ struct vcpu_svm *svm = to_svm(vcpu);
+ bool flat = svm->dfr_reg == APIC_DFR_FLAT;
+ u32 *entry = avic_get_logical_id_entry(vcpu, svm->ldr_reg, flat);
+
+ if (entry)
+ WRITE_ONCE(*entry, (u32) ~AVIC_LOGICAL_ID_ENTRY_VALID_MASK);
+}
+
static int avic_handle_ldr_update(struct kvm_vcpu *vcpu)
{
- int ret;
+ int ret = 0;
struct vcpu_svm *svm = to_svm(vcpu);
u32 ldr = kvm_lapic_get_reg(vcpu->arch.apic, APIC_LDR);
- if (!ldr)
- return 1;
+ if (ldr == svm->ldr_reg)
+ return 0;
- ret = avic_ldr_write(vcpu, vcpu->vcpu_id, ldr, true);
- if (ret && svm->ldr_reg) {
- avic_ldr_write(vcpu, 0, svm->ldr_reg, false);
- svm->ldr_reg = 0;
- } else {
+ avic_invalidate_logical_id_entry(vcpu);
+
+ if (ldr)
+ ret = avic_ldr_write(vcpu, vcpu->vcpu_id, ldr);
+
+ if (!ret)
svm->ldr_reg = ldr;
- }
+
return ret;
}
@@ -4637,27 +4645,16 @@ static int avic_handle_apic_id_update(struct kvm_vcpu *vcpu)
return 0;
}
-static int avic_handle_dfr_update(struct kvm_vcpu *vcpu)
+static void avic_handle_dfr_update(struct kvm_vcpu *vcpu)
{
struct vcpu_svm *svm = to_svm(vcpu);
- struct kvm_svm *kvm_svm = to_kvm_svm(vcpu->kvm);
u32 dfr = kvm_lapic_get_reg(vcpu->arch.apic, APIC_DFR);
- u32 mod = (dfr >> 28) & 0xf;
-
- /*
- * We assume that all local APICs are using the same type.
- * If this changes, we need to flush the AVIC logical
- * APID id table.
- */
- if (kvm_svm->ldr_mode == mod)
- return 0;
- clear_page(page_address(kvm_svm->avic_logical_id_table_page));
- kvm_svm->ldr_mode = mod;
+ if (svm->dfr_reg == dfr)
+ return;
- if (svm->ldr_reg)
- avic_handle_ldr_update(vcpu);
- return 0;
+ avic_invalidate_logical_id_entry(vcpu);
+ svm->dfr_reg = dfr;
}
static int avic_unaccel_trap_write(struct vcpu_svm *svm)
@@ -6163,8 +6160,7 @@ static inline void avic_post_state_restore(struct kvm_vcpu *vcpu)
{
if (avic_handle_apic_id_update(vcpu) != 0)
return;
- if (avic_handle_dfr_update(vcpu) != 0)
- return;
+ avic_handle_dfr_update(vcpu);
avic_handle_ldr_update(vcpu);
}