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-rw-r--r--Documentation/virt/kvm/api.rst24
-rw-r--r--arch/arm64/kvm/psci.c3
-rw-r--r--arch/riscv/kvm/vcpu_sbi.c5
-rw-r--r--arch/x86/kvm/mmu.h24
-rw-r--r--arch/x86/kvm/mmu/mmu.c57
-rw-r--r--arch/x86/kvm/mmu/spte.h6
-rw-r--r--arch/x86/kvm/mmu/tdp_mmu.c15
-rw-r--r--arch/x86/kvm/x86.c8
-rw-r--r--include/uapi/linux/kvm.h10
-rw-r--r--virt/kvm/kvm_main.c1
10 files changed, 121 insertions, 32 deletions
diff --git a/Documentation/virt/kvm/api.rst b/Documentation/virt/kvm/api.rst
index 85c7abc51af5..4a900cdbc62e 100644
--- a/Documentation/virt/kvm/api.rst
+++ b/Documentation/virt/kvm/api.rst
@@ -5986,16 +5986,16 @@ should put the acknowledged interrupt vector into the 'epr' field.
#define KVM_SYSTEM_EVENT_RESET 2
#define KVM_SYSTEM_EVENT_CRASH 3
__u32 type;
- __u64 flags;
+ __u32 ndata;
+ __u64 data[16];
} system_event;
If exit_reason is KVM_EXIT_SYSTEM_EVENT then the vcpu has triggered
a system-level event using some architecture specific mechanism (hypercall
or some special instruction). In case of ARM64, this is triggered using
-HVC instruction based PSCI call from the vcpu. The 'type' field describes
-the system-level event type. The 'flags' field describes architecture
-specific flags for the system-level event.
+HVC instruction based PSCI call from the vcpu.
+The 'type' field describes the system-level event type.
Valid values for 'type' are:
- KVM_SYSTEM_EVENT_SHUTDOWN -- the guest has requested a shutdown of the
@@ -6010,10 +6010,20 @@ Valid values for 'type' are:
to ignore the request, or to gather VM memory core dump and/or
reset/shutdown of the VM.
-Valid flags are:
+If KVM_CAP_SYSTEM_EVENT_DATA is present, the 'data' field can contain
+architecture specific information for the system-level event. Only
+the first `ndata` items (possibly zero) of the data array are valid.
- - KVM_SYSTEM_EVENT_RESET_FLAG_PSCI_RESET2 (arm64 only) -- the guest issued
- a SYSTEM_RESET2 call according to v1.1 of the PSCI specification.
+ - for arm64, data[0] is set to KVM_SYSTEM_EVENT_RESET_FLAG_PSCI_RESET2 if
+ the guest issued a SYSTEM_RESET2 call according to v1.1 of the PSCI
+ specification.
+
+ - for RISC-V, data[0] is set to the value of the second argument of the
+ ``sbi_system_reset`` call.
+
+Previous versions of Linux defined a `flags` member in this struct. The
+field is now aliased to `data[0]`. Userspace can assume that it is only
+written if ndata is greater than 0.
::
diff --git a/arch/arm64/kvm/psci.c b/arch/arm64/kvm/psci.c
index baac2b405f23..708d80e8e60d 100644
--- a/arch/arm64/kvm/psci.c
+++ b/arch/arm64/kvm/psci.c
@@ -181,7 +181,8 @@ static void kvm_prepare_system_event(struct kvm_vcpu *vcpu, u32 type, u64 flags)
memset(&vcpu->run->system_event, 0, sizeof(vcpu->run->system_event));
vcpu->run->system_event.type = type;
- vcpu->run->system_event.flags = flags;
+ vcpu->run->system_event.ndata = 1;
+ vcpu->run->system_event.data[0] = flags;
vcpu->run->exit_reason = KVM_EXIT_SYSTEM_EVENT;
}
diff --git a/arch/riscv/kvm/vcpu_sbi.c b/arch/riscv/kvm/vcpu_sbi.c
index a09ecb97b890..d45e7da3f0d3 100644
--- a/arch/riscv/kvm/vcpu_sbi.c
+++ b/arch/riscv/kvm/vcpu_sbi.c
@@ -83,7 +83,7 @@ void kvm_riscv_vcpu_sbi_forward(struct kvm_vcpu *vcpu, struct kvm_run *run)
void kvm_riscv_vcpu_sbi_system_reset(struct kvm_vcpu *vcpu,
struct kvm_run *run,
- u32 type, u64 flags)
+ u32 type, u64 reason)
{
unsigned long i;
struct kvm_vcpu *tmp;
@@ -94,7 +94,8 @@ void kvm_riscv_vcpu_sbi_system_reset(struct kvm_vcpu *vcpu,
memset(&run->system_event, 0, sizeof(run->system_event));
run->system_event.type = type;
- run->system_event.flags = flags;
+ run->system_event.ndata = 1;
+ run->system_event.data[0] = reason;
run->exit_reason = KVM_EXIT_SYSTEM_EVENT;
}
diff --git a/arch/x86/kvm/mmu.h b/arch/x86/kvm/mmu.h
index e6cae6f22683..a335e7f1f69e 100644
--- a/arch/x86/kvm/mmu.h
+++ b/arch/x86/kvm/mmu.h
@@ -65,6 +65,30 @@ static __always_inline u64 rsvd_bits(int s, int e)
return ((2ULL << (e - s)) - 1) << s;
}
+/*
+ * The number of non-reserved physical address bits irrespective of features
+ * that repurpose legal bits, e.g. MKTME.
+ */
+extern u8 __read_mostly shadow_phys_bits;
+
+static inline gfn_t kvm_mmu_max_gfn(void)
+{
+ /*
+ * Note that this uses the host MAXPHYADDR, not the guest's.
+ * EPT/NPT cannot support GPAs that would exceed host.MAXPHYADDR;
+ * assuming KVM is running on bare metal, guest accesses beyond
+ * host.MAXPHYADDR will hit a #PF(RSVD) and never cause a vmexit
+ * (either EPT Violation/Misconfig or #NPF), and so KVM will never
+ * install a SPTE for such addresses. If KVM is running as a VM
+ * itself, on the other hand, it might see a MAXPHYADDR that is less
+ * than hardware's real MAXPHYADDR. Using the host MAXPHYADDR
+ * disallows such SPTEs entirely and simplifies the TDP MMU.
+ */
+ int max_gpa_bits = likely(tdp_enabled) ? shadow_phys_bits : 52;
+
+ return (1ULL << (max_gpa_bits - PAGE_SHIFT)) - 1;
+}
+
void kvm_mmu_set_mmio_spte_mask(u64 mmio_value, u64 mmio_mask, u64 access_mask);
void kvm_mmu_set_ept_masks(bool has_ad_bits, bool has_exec_only);
diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c
index f9080ee50ffa..64a2a7e2be90 100644
--- a/arch/x86/kvm/mmu/mmu.c
+++ b/arch/x86/kvm/mmu/mmu.c
@@ -2804,8 +2804,12 @@ static int host_pfn_mapping_level(struct kvm *kvm, gfn_t gfn, kvm_pfn_t pfn,
const struct kvm_memory_slot *slot)
{
unsigned long hva;
- pte_t *pte;
- int level;
+ unsigned long flags;
+ int level = PG_LEVEL_4K;
+ pgd_t pgd;
+ p4d_t p4d;
+ pud_t pud;
+ pmd_t pmd;
if (!PageCompound(pfn_to_page(pfn)) && !kvm_is_zone_device_pfn(pfn))
return PG_LEVEL_4K;
@@ -2820,10 +2824,43 @@ static int host_pfn_mapping_level(struct kvm *kvm, gfn_t gfn, kvm_pfn_t pfn,
*/
hva = __gfn_to_hva_memslot(slot, gfn);
- pte = lookup_address_in_mm(kvm->mm, hva, &level);
- if (unlikely(!pte))
- return PG_LEVEL_4K;
+ /*
+ * Lookup the mapping level in the current mm. The information
+ * may become stale soon, but it is safe to use as long as
+ * 1) mmu_notifier_retry was checked after taking mmu_lock, and
+ * 2) mmu_lock is taken now.
+ *
+ * We still need to disable IRQs to prevent concurrent tear down
+ * of page tables.
+ */
+ local_irq_save(flags);
+
+ pgd = READ_ONCE(*pgd_offset(kvm->mm, hva));
+ if (pgd_none(pgd))
+ goto out;
+
+ p4d = READ_ONCE(*p4d_offset(&pgd, hva));
+ if (p4d_none(p4d) || !p4d_present(p4d))
+ goto out;
+ pud = READ_ONCE(*pud_offset(&p4d, hva));
+ if (pud_none(pud) || !pud_present(pud))
+ goto out;
+
+ if (pud_large(pud)) {
+ level = PG_LEVEL_1G;
+ goto out;
+ }
+
+ pmd = READ_ONCE(*pmd_offset(&pud, hva));
+ if (pmd_none(pmd) || !pmd_present(pmd))
+ goto out;
+
+ if (pmd_large(pmd))
+ level = PG_LEVEL_2M;
+
+out:
+ local_irq_restore(flags);
return level;
}
@@ -2992,9 +3029,15 @@ static bool handle_abnormal_pfn(struct kvm_vcpu *vcpu, struct kvm_page_fault *fa
/*
* If MMIO caching is disabled, emulate immediately without
* touching the shadow page tables as attempting to install an
- * MMIO SPTE will just be an expensive nop.
+ * MMIO SPTE will just be an expensive nop. Do not cache MMIO
+ * whose gfn is greater than host.MAXPHYADDR, any guest that
+ * generates such gfns is running nested and is being tricked
+ * by L0 userspace (you can observe gfn > L1.MAXPHYADDR if
+ * and only if L1's MAXPHYADDR is inaccurate with respect to
+ * the hardware's).
*/
- if (unlikely(!shadow_mmio_value)) {
+ if (unlikely(!shadow_mmio_value) ||
+ unlikely(fault->gfn > kvm_mmu_max_gfn())) {
*ret_val = RET_PF_EMULATE;
return true;
}
diff --git a/arch/x86/kvm/mmu/spte.h b/arch/x86/kvm/mmu/spte.h
index 73f12615416f..e4abeb5df1b1 100644
--- a/arch/x86/kvm/mmu/spte.h
+++ b/arch/x86/kvm/mmu/spte.h
@@ -201,12 +201,6 @@ static inline bool is_removed_spte(u64 spte)
*/
extern u64 __read_mostly shadow_nonpresent_or_rsvd_lower_gfn_mask;
-/*
- * The number of non-reserved physical address bits irrespective of features
- * that repurpose legal bits, e.g. MKTME.
- */
-extern u8 __read_mostly shadow_phys_bits;
-
static inline bool is_mmio_spte(u64 spte)
{
return (spte & shadow_mmio_mask) == shadow_mmio_value &&
diff --git a/arch/x86/kvm/mmu/tdp_mmu.c b/arch/x86/kvm/mmu/tdp_mmu.c
index c472769e0300..edc68538819b 100644
--- a/arch/x86/kvm/mmu/tdp_mmu.c
+++ b/arch/x86/kvm/mmu/tdp_mmu.c
@@ -815,14 +815,15 @@ static inline bool __must_check tdp_mmu_iter_cond_resched(struct kvm *kvm,
return iter->yielded;
}
-static inline gfn_t tdp_mmu_max_gfn_host(void)
+static inline gfn_t tdp_mmu_max_gfn_exclusive(void)
{
/*
- * Bound TDP MMU walks at host.MAXPHYADDR, guest accesses beyond that
- * will hit a #PF(RSVD) and never hit an EPT Violation/Misconfig / #NPF,
- * and so KVM will never install a SPTE for such addresses.
+ * Bound TDP MMU walks at host.MAXPHYADDR. KVM disallows memslots with
+ * a gpa range that would exceed the max gfn, and KVM does not create
+ * MMIO SPTEs for "impossible" gfns, instead sending such accesses down
+ * the slow emulation path every time.
*/
- return 1ULL << (shadow_phys_bits - PAGE_SHIFT);
+ return kvm_mmu_max_gfn() + 1;
}
static void __tdp_mmu_zap_root(struct kvm *kvm, struct kvm_mmu_page *root,
@@ -830,7 +831,7 @@ static void __tdp_mmu_zap_root(struct kvm *kvm, struct kvm_mmu_page *root,
{
struct tdp_iter iter;
- gfn_t end = tdp_mmu_max_gfn_host();
+ gfn_t end = tdp_mmu_max_gfn_exclusive();
gfn_t start = 0;
for_each_tdp_pte_min_level(iter, root, zap_level, start, end) {
@@ -923,7 +924,7 @@ static bool tdp_mmu_zap_leafs(struct kvm *kvm, struct kvm_mmu_page *root,
{
struct tdp_iter iter;
- end = min(end, tdp_mmu_max_gfn_host());
+ end = min(end, tdp_mmu_max_gfn_exclusive());
lockdep_assert_held_write(&kvm->mmu_lock);
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index a6ab19afc638..4790f0d7d40b 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -10020,12 +10020,14 @@ static int vcpu_enter_guest(struct kvm_vcpu *vcpu)
if (kvm_check_request(KVM_REQ_HV_CRASH, vcpu)) {
vcpu->run->exit_reason = KVM_EXIT_SYSTEM_EVENT;
vcpu->run->system_event.type = KVM_SYSTEM_EVENT_CRASH;
+ vcpu->run->system_event.ndata = 0;
r = 0;
goto out;
}
if (kvm_check_request(KVM_REQ_HV_RESET, vcpu)) {
vcpu->run->exit_reason = KVM_EXIT_SYSTEM_EVENT;
vcpu->run->system_event.type = KVM_SYSTEM_EVENT_RESET;
+ vcpu->run->system_event.ndata = 0;
r = 0;
goto out;
}
@@ -12009,8 +12011,12 @@ int kvm_arch_prepare_memory_region(struct kvm *kvm,
struct kvm_memory_slot *new,
enum kvm_mr_change change)
{
- if (change == KVM_MR_CREATE || change == KVM_MR_MOVE)
+ if (change == KVM_MR_CREATE || change == KVM_MR_MOVE) {
+ if ((new->base_gfn + new->npages - 1) > kvm_mmu_max_gfn())
+ return -EINVAL;
+
return kvm_alloc_memslot_metadata(kvm, new);
+ }
if (change == KVM_MR_FLAGS_ONLY)
memcpy(&new->arch, &old->arch, sizeof(old->arch));
diff --git a/include/uapi/linux/kvm.h b/include/uapi/linux/kvm.h
index 91a6fe4e02c0..6a184d260c7f 100644
--- a/include/uapi/linux/kvm.h
+++ b/include/uapi/linux/kvm.h
@@ -445,7 +445,13 @@ struct kvm_run {
#define KVM_SYSTEM_EVENT_RESET 2
#define KVM_SYSTEM_EVENT_CRASH 3
__u32 type;
- __u64 flags;
+ __u32 ndata;
+ union {
+#ifndef __KERNEL__
+ __u64 flags;
+#endif
+ __u64 data[16];
+ };
} system_event;
/* KVM_EXIT_S390_STSI */
struct {
@@ -1144,6 +1150,8 @@ struct kvm_ppc_resize_hpt {
#define KVM_CAP_S390_MEM_OP_EXTENSION 211
#define KVM_CAP_PMU_CAPABILITY 212
#define KVM_CAP_DISABLE_QUIRKS2 213
+/* #define KVM_CAP_VM_TSC_CONTROL 214 */
+#define KVM_CAP_SYSTEM_EVENT_DATA 215
#ifdef KVM_CAP_IRQ_ROUTING
diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
index f30bb8c16f26..6d971fb1b08d 100644
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -4354,6 +4354,7 @@ static long kvm_vm_ioctl_check_extension_generic(struct kvm *kvm, long arg)
return 0;
#endif
case KVM_CAP_BINARY_STATS_FD:
+ case KVM_CAP_SYSTEM_EVENT_DATA:
return 1;
default:
break;
generated by cgit v1.2.3 (git 2.39.1) at 2024-11-07 18:53:07 +0000