From: Mihai Donțu <mdontu@xxxxxxxxxxxxxxx>
Using the KVMI_CONTROL_CR command, the introspection tool subscribes to
KVMI_EVENT_CR events that will be sent when CR{0,3,4} is going to
be changed.
Signed-off-by: Mihai Donțu <mdontu@xxxxxxxxxxxxxxx>
Signed-off-by: Adalbert Lazăr <alazar@xxxxxxxxxxxxxxx>
---
Documentation/virtual/kvm/kvmi.rst | 70 ++++++++++++++++++++++
arch/x86/include/asm/kvm_host.h | 2 +
arch/x86/include/asm/kvmi_host.h | 16 +++++
arch/x86/include/uapi/asm/kvmi.h | 18 ++++++
arch/x86/kvm/kvmi.c | 95 ++++++++++++++++++++++++++++++
arch/x86/kvm/svm.c | 5 ++
arch/x86/kvm/vmx/vmx.c | 14 +++++
arch/x86/kvm/x86.c | 19 +++++-
virt/kvm/kvmi_int.h | 7 +++
virt/kvm/kvmi_msg.c | 13 ++++
10 files changed, 258 insertions(+), 1 deletion(-)
diff --git a/Documentation/virtual/kvm/kvmi.rst b/Documentation/virtual/kvm/kvmi.rst
index 1eaed7c61148..2e6e285c8e2e 100644
--- a/Documentation/virtual/kvm/kvmi.rst
+++ b/Documentation/virtual/kvm/kvmi.rst
@@ -1007,6 +1007,41 @@ order to be notified if the expection was not delivered.
* -KVM_EINVAL - padding is not zero
* -KVM_EAGAIN - the selected vCPU can't be introspected yet
+21. KVMI_CONTROL_CR
+-------------------
+
+:Architectures: x86
+:Versions: >= 1
+:Parameters:
+
+::
+
+ struct kvmi_vcpu_hdr;
+ struct kvmi_control_cr {
+ __u8 enable;
+ __u8 padding1;
+ __u16 padding2;
+ __u32 cr;
+ };
+
+:Returns:
+
+::
+
+ struct kvmi_error_code
+
+Enables/disables introspection for a specific control register and must
+be used in addition to *KVMI_CONTROL_EVENTS* with the *KVMI_EVENT_CR*
+ID set.
+
+:Errors:
+
+* -KVM_EINVAL - the selected vCPU is invalid
+* -KVM_EINVAL - the specified control register is not part of the CR0, CR3
+ or CR4 set
+* -KVM_EINVAL - padding is not zero
+* -KVM_EAGAIN - the selected vCPU can't be introspected yet
+
Events
======
@@ -1238,3 +1273,38 @@ introspection has been enabled for this event (see *KVMI_CONTROL_EVENTS*).
``kvmi_event``, exception/interrupt number (vector), exception/interrupt
type, exception code (``error_code``) and CR2 are sent to the introspector.
+6. KVMI_EVENT_CR
+----------------
+
+:Architectures: x86
+:Versions: >= 1
+:Actions: CONTINUE, CRASH
+:Parameters:
+
+::
+
+ struct kvmi_event;
+ struct kvmi_event_cr {
+ __u16 cr;
+ __u16 padding[3];
+ __u64 old_value;
+ __u64 new_value;
+ };
+
+:Returns:
+
+::
+
+ struct kvmi_vcpu_hdr;
+ struct kvmi_event_reply;
+ struct kvmi_event_cr_reply {
+ __u64 new_val;
+ };
+
+This event is sent when a control register is going to be changed and the
+introspection has been enabled for this event and for this specific
+register (see **KVMI_CONTROL_EVENTS**).
+
+``kvmi_event``, the control register number, the old value and the new value
+are sent to the introspector. The *CONTINUE* action will set the ``new_val``.
+
diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
index 7ee6e1ff5ee9..22f08f2732cc 100644
--- a/arch/x86/include/asm/kvm_host.h
+++ b/arch/x86/include/asm/kvm_host.h
@@ -1013,6 +1013,7 @@ struct kvm_x86_ops {
bool (*has_emulated_msr)(int index);
void (*cpuid_update)(struct kvm_vcpu *vcpu);
+ void (*cr3_write_exiting)(struct kvm_vcpu *vcpu, bool enable);
bool (*nested_pagefault)(struct kvm_vcpu *vcpu);
bool (*spt_fault)(struct kvm_vcpu *vcpu);
@@ -1622,5 +1623,6 @@ static inline int kvm_cpu_get_apicid(int mps_cpu)
bool kvm_mmu_nested_pagefault(struct kvm_vcpu *vcpu);
bool kvm_spt_fault(struct kvm_vcpu *vcpu);
+void kvm_control_cr3_write_exiting(struct kvm_vcpu *vcpu, bool enable);
#endif /* _ASM_X86_KVM_HOST_H */
diff --git a/arch/x86/include/asm/kvmi_host.h b/arch/x86/include/asm/kvmi_host.h
index 7ab6dd71a0c2..83a098dc8939 100644
--- a/arch/x86/include/asm/kvmi_host.h
+++ b/arch/x86/include/asm/kvmi_host.h
@@ -9,4 +9,20 @@ struct kvmi_arch_mem_access {
unsigned long active[KVM_PAGE_TRACK_MAX][BITS_TO_LONGS(KVM_MEM_SLOTS_NUM)];
};
+#ifdef CONFIG_KVM_INTROSPECTION
+
+bool kvmi_cr_event(struct kvm_vcpu *vcpu, unsigned int cr,
+ unsigned long old_value, unsigned long *new_value);
+
+#else /* CONFIG_KVM_INTROSPECTION */
+
+static inline bool kvmi_cr_event(struct kvm_vcpu *vcpu, unsigned int cr,
+ unsigned long old_value,
+ unsigned long *new_value)
+{
+ return true;
+}
+
+#endif /* CONFIG_KVM_INTROSPECTION */
+
#endif /* _ASM_X86_KVMI_HOST_H */
diff --git a/arch/x86/include/uapi/asm/kvmi.h b/arch/x86/include/uapi/asm/kvmi.h
index b074ad735e84..c983b4bd2c72 100644
--- a/arch/x86/include/uapi/asm/kvmi.h
+++ b/arch/x86/include/uapi/asm/kvmi.h
@@ -61,4 +61,22 @@ struct kvmi_get_cpuid_reply {
__u32 edx;
};
+struct kvmi_control_cr {
+ __u8 enable;
+ __u8 padding1;
+ __u16 padding2;
+ __u32 cr;
+};
+
+struct kvmi_event_cr {
+ __u16 cr;
+ __u16 padding[3];
+ __u64 old_value;
+ __u64 new_value;
+};
+
+struct kvmi_event_cr_reply {
+ __u64 new_val;
+};
+
#endif /* _UAPI_ASM_X86_KVMI_H */
diff --git a/arch/x86/kvm/kvmi.c b/arch/x86/kvm/kvmi.c
index 8c18030d12f4..b3cab0db6a70 100644
--- a/arch/x86/kvm/kvmi.c
+++ b/arch/x86/kvm/kvmi.c
@@ -171,6 +171,72 @@ void kvmi_arch_setup_event(struct kvm_vcpu *vcpu, struct kvmi_event *ev)
kvmi_get_msrs(vcpu, event);
}
+static u32 kvmi_send_cr(struct kvm_vcpu *vcpu, u32 cr, u64 old_value,
+ u64 new_value, u64 *ret_value)
+{
+ struct kvmi_event_cr e = {
+ .cr = cr,
+ .old_value = old_value,
+ .new_value = new_value
+ };
+ struct kvmi_event_cr_reply r;
+ int err, action;
+
+ err = kvmi_send_event(vcpu, KVMI_EVENT_CR, &e, sizeof(e),
+ &r, sizeof(r), &action);
+ if (err) {
+ *ret_value = new_value;
+ return KVMI_EVENT_ACTION_CONTINUE;
+ }
+
+ *ret_value = r.new_val;
+ return action;
+}
+
+static bool __kvmi_cr_event(struct kvm_vcpu *vcpu, unsigned int cr,
+ unsigned long old_value, unsigned long *new_value)
+{
+ u64 ret_value;
+ u32 action;
+ bool ret = false;
+
+ if (!test_bit(cr, IVCPU(vcpu)->cr_mask))
+ return true;
+
+ action = kvmi_send_cr(vcpu, cr, old_value, *new_value, &ret_value);
+ switch (action) {
+ case KVMI_EVENT_ACTION_CONTINUE:
+ *new_value = ret_value;
+ ret = true;
+ break;
+ default:
+ kvmi_handle_common_event_actions(vcpu, action, "CR");
+ }
+
+ return ret;
+}
+
+bool kvmi_cr_event(struct kvm_vcpu *vcpu, unsigned int cr,
+ unsigned long old_value, unsigned long *new_value)
+{
+ struct kvmi *ikvm;
+ bool ret = true;
+
+ if (old_value == *new_value)
+ return true;
+
+ ikvm = kvmi_get(vcpu->kvm);
+ if (!ikvm)
+ return true;
+
+ if (is_event_enabled(vcpu, KVMI_EVENT_CR))
+ ret = __kvmi_cr_event(vcpu, cr, old_value, new_value);
+
+ kvmi_put(vcpu->kvm);
+
+ return ret;
+}
+
bool kvmi_arch_pf_event(struct kvm_vcpu *vcpu, gpa_t gpa, gva_t gva,
u8 access)
{
@@ -349,6 +415,35 @@ int kvmi_arch_cmd_inject_exception(struct kvm_vcpu *vcpu, u8 vector,
return 0;
}
+int kvmi_arch_cmd_control_cr(struct kvm_vcpu *vcpu,
+ const struct kvmi_control_cr *req)
+{
+ struct kvmi_vcpu *ivcpu = IVCPU(vcpu);
+ u32 cr = req->cr;
+
+ if (req->padding1 || req->padding2)
+ return -KVM_EINVAL;
+
+ switch (cr) {
+ case 0:
+ break;
+ case 3:
+ kvm_control_cr3_write_exiting(vcpu, req->enable);
+ break;
+ case 4:
+ break;
+ default:
+ return -KVM_EINVAL;
+ }
+
+ if (req->enable)
+ set_bit(cr, ivcpu->cr_mask);
+ else
+ clear_bit(cr, ivcpu->cr_mask);
+
+ return 0;
+}
+
static const struct {
unsigned int allow_bit;
enum kvm_page_track_mode track_mode;
diff --git a/arch/x86/kvm/svm.c b/arch/x86/kvm/svm.c
index 6b533698c73d..fc78b0052dee 100644
--- a/arch/x86/kvm/svm.c
+++ b/arch/x86/kvm/svm.c
@@ -7110,6 +7110,10 @@ static bool svm_spt_fault(struct kvm_vcpu *vcpu)
return (svm->vmcb->control.exit_code == SVM_EXIT_NPF);
}
+static void svm_cr3_write_exiting(struct kvm_vcpu *vcpu, bool enable)
+{
+}
+
static struct kvm_x86_ops svm_x86_ops __ro_after_init = {
.cpu_has_kvm_support = has_svm,
.disabled_by_bios = is_disabled,
@@ -7121,6 +7125,7 @@ static struct kvm_x86_ops svm_x86_ops __ro_after_init = {
.cpu_has_accelerated_tpr = svm_cpu_has_accelerated_tpr,
.has_emulated_msr = svm_has_emulated_msr,
+ .cr3_write_exiting = svm_cr3_write_exiting,
.nested_pagefault = svm_nested_pagefault,
.spt_fault = svm_spt_fault,
diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c
index 5d4b61aaff9a..6450c8c44771 100644
--- a/arch/x86/kvm/vmx/vmx.c
+++ b/arch/x86/kvm/vmx/vmx.c
@@ -7784,6 +7784,19 @@ static __exit void hardware_unsetup(void)
free_kvm_area();
}
+static void vmx_cr3_write_exiting(struct kvm_vcpu *vcpu,
+ bool enable)
+{
+ if (enable)
+ vmcs_set_bits(CPU_BASED_VM_EXEC_CONTROL,
+ CPU_BASED_CR3_LOAD_EXITING);
+ else
+ vmcs_clear_bits(CPU_BASED_VM_EXEC_CONTROL,
+ CPU_BASED_CR3_LOAD_EXITING);
+
+ /* TODO: nested ? vmcs12->cpu_based_vm_exec_control */
+}
+
static bool vmx_nested_pagefault(struct kvm_vcpu *vcpu)
{
if (vcpu->arch.exit_qualification & EPT_VIOLATION_GVA_TRANSLATED)
@@ -7831,6 +7844,7 @@ static struct kvm_x86_ops vmx_x86_ops __ro_after_init = {
.cpu_has_accelerated_tpr = report_flexpriority,
.has_emulated_msr = vmx_has_emulated_msr,
+ .cr3_write_exiting = vmx_cr3_write_exiting,
.nested_pagefault = vmx_nested_pagefault,
.spt_fault = vmx_spt_fault,
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index e38c0b95a0e7..2cd146ccc6ff 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -22,6 +22,7 @@
#include <linux/kvm_host.h>
#include <uapi/linux/kvmi.h>
#include <linux/kvmi.h>
+#include <asm/kvmi_host.h>
#include "irq.h"
#include "mmu.h"
#include "i8254.h"
@@ -777,6 +778,9 @@ int kvm_set_cr0(struct kvm_vcpu *vcpu, unsigned long cr0)
if (!(cr0 & X86_CR0_PG) && kvm_read_cr4_bits(vcpu, X86_CR4_PCIDE))
return 1;
+ if (!kvmi_cr_event(vcpu, 0, old_cr0, &cr0))
+ return 1;
+
kvm_x86_ops->set_cr0(vcpu, cr0);
if ((cr0 ^ old_cr0) & X86_CR0_PG) {
@@ -921,6 +925,9 @@ int kvm_set_cr4(struct kvm_vcpu *vcpu, unsigned long cr4)
return 1;
}
+ if (!kvmi_cr_event(vcpu, 4, old_cr4, &cr4))
+ return 1;
+
if (kvm_x86_ops->set_cr4(vcpu, cr4))
return 1;
@@ -937,6 +944,7 @@ EXPORT_SYMBOL_GPL(kvm_set_cr4);
int kvm_set_cr3(struct kvm_vcpu *vcpu, unsigned long cr3)
{
+ unsigned long old_cr3 = kvm_read_cr3(vcpu);
bool skip_tlb_flush = false;
#ifdef CONFIG_X86_64
bool pcid_enabled = kvm_read_cr4_bits(vcpu, X86_CR4_PCIDE);
@@ -947,7 +955,7 @@ int kvm_set_cr3(struct kvm_vcpu *vcpu, unsigned long cr3)
}
#endif
- if (cr3 == kvm_read_cr3(vcpu) && !pdptrs_changed(vcpu)) {
+ if (cr3 == old_cr3 && !pdptrs_changed(vcpu)) {
if (!skip_tlb_flush) {
kvm_mmu_sync_roots(vcpu);
kvm_make_request(KVM_REQ_TLB_FLUSH, vcpu);
@@ -962,6 +970,9 @@ int kvm_set_cr3(struct kvm_vcpu *vcpu, unsigned long cr3)
!load_pdptrs(vcpu, vcpu->arch.walk_mmu, cr3))
return 1;
+ if (!kvmi_cr_event(vcpu, 3, old_cr3, &cr3))
+ return 1;
+
kvm_mmu_new_cr3(vcpu, cr3, skip_tlb_flush);
vcpu->arch.cr3 = cr3;
__set_bit(VCPU_EXREG_CR3, (ulong *)&vcpu->arch.regs_avail);
@@ -10072,6 +10083,12 @@ bool kvm_vector_hashing_enabled(void)
}
EXPORT_SYMBOL_GPL(kvm_vector_hashing_enabled);
+void kvm_control_cr3_write_exiting(struct kvm_vcpu *vcpu, bool enable)
+{
+ kvm_x86_ops->cr3_write_exiting(vcpu, enable);
+}
+EXPORT_SYMBOL(kvm_control_cr3_write_exiting);
+
bool kvm_spt_fault(struct kvm_vcpu *vcpu)
{
return kvm_x86_ops->spt_fault(vcpu);
diff --git a/virt/kvm/kvmi_int.h b/virt/kvm/kvmi_int.h
index 2eadeb6efde8..c92be3c2c131 100644
--- a/virt/kvm/kvmi_int.h
+++ b/virt/kvm/kvmi_int.h
@@ -26,6 +26,8 @@
#define IVCPU(vcpu) ((struct kvmi_vcpu *)((vcpu)->kvmi))
+#define KVMI_NUM_CR 9
+
#define KVMI_CTX_DATA_SIZE FIELD_SIZEOF(struct kvmi_event_pf_reply, ctx_data)
#define KVMI_MSG_SIZE_ALLOC (sizeof(struct kvmi_msg_hdr) + KVMI_MSG_SIZE)
@@ -117,6 +119,7 @@ struct kvmi_vcpu {
struct kvm_regs delayed_regs;
DECLARE_BITMAP(ev_mask, KVMI_NUM_EVENTS);
+ DECLARE_BITMAP(cr_mask, KVMI_NUM_CR);
struct list_head job_list;
spinlock_t job_lock;
@@ -204,6 +207,8 @@ int kvmi_cmd_control_events(struct kvm_vcpu *vcpu, unsigned int event_id,
int kvmi_cmd_control_vm_events(struct kvmi *ikvm, unsigned int event_id,
bool enable);
int kvmi_cmd_pause_vcpu(struct kvm_vcpu *vcpu, bool wait);
+struct kvmi * __must_check kvmi_get(struct kvm *kvm);
+void kvmi_put(struct kvm *kvm);
int kvmi_run_jobs_and_wait(struct kvm_vcpu *vcpu);
void kvmi_post_reply(struct kvm_vcpu *vcpu);
int kvmi_add_job(struct kvm_vcpu *vcpu,
@@ -251,5 +256,7 @@ int kvmi_arch_cmd_get_vcpu_info(struct kvm_vcpu *vcpu,
int kvmi_arch_cmd_inject_exception(struct kvm_vcpu *vcpu, u8 vector,
bool error_code_valid, u32 error_code,
u64 address);
+int kvmi_arch_cmd_control_cr(struct kvm_vcpu *vcpu,
+ const struct kvmi_control_cr *req);
#endif
diff --git a/virt/kvm/kvmi_msg.c b/virt/kvm/kvmi_msg.c
index e80d28dbb061..d4f5459722bb 100644
--- a/virt/kvm/kvmi_msg.c
+++ b/virt/kvm/kvmi_msg.c
@@ -24,6 +24,7 @@ static const char *const msg_IDs[] = {
[KVMI_CHECK_COMMAND] = "KVMI_CHECK_COMMAND",
[KVMI_CHECK_EVENT] = "KVMI_CHECK_EVENT",
[KVMI_CONTROL_CMD_RESPONSE] = "KVMI_CONTROL_CMD_RESPONSE",
+ [KVMI_CONTROL_CR] = "KVMI_CONTROL_CR",
[KVMI_CONTROL_EVENTS] = "KVMI_CONTROL_EVENTS",
[KVMI_CONTROL_SPP] = "KVMI_CONTROL_SPP",
[KVMI_CONTROL_VM_EVENTS] = "KVMI_CONTROL_VM_EVENTS",
@@ -662,6 +663,17 @@ static int handle_control_events(struct kvm_vcpu *vcpu,
return reply_cb(vcpu, msg, ec, NULL, 0);
}
+static int handle_control_cr(struct kvm_vcpu *vcpu,
+ const struct kvmi_msg_hdr *msg, const void *req,
+ vcpu_reply_fct reply_cb)
+{
+ int ec;
+
+ ec = kvmi_arch_cmd_control_cr(vcpu, req);
+
+ return reply_cb(vcpu, msg, ec, NULL, 0);
+}
+
static int handle_get_cpuid(struct kvm_vcpu *vcpu,
const struct kvmi_msg_hdr *msg,
const void *req, vcpu_reply_fct reply_cb)
@@ -685,6 +697,7 @@ static int handle_get_cpuid(struct kvm_vcpu *vcpu,
static int(*const msg_vcpu[])(struct kvm_vcpu *,
const struct kvmi_msg_hdr *, const void *,
vcpu_reply_fct) = {
+ [KVMI_CONTROL_CR] = handle_control_cr,
[KVMI_CONTROL_EVENTS] = handle_control_events,
[KVMI_EVENT_REPLY] = handle_event_reply,
[KVMI_GET_CPUID] = handle_get_cpuid,
