From: Mihai Donțu <mdo...@bitdefender.com>
Based on the common structure (kvmi_vcpu_hdr) used for all vCPU commands,
the receiving thread validates and dispatches the message to the proper
vCPU (adding the handling function to its jobs list).
Signed-off-by: Mihai Donțu <mdo...@bitdefender.com>
Co-developed-by: Nicușor Cîțu <nicu.c...@icloud.com>
Signed-off-by: Nicușor Cîțu <nicu.c...@icloud.com>
Co-developed-by: Adalbert Lazăr <ala...@bitdefender.com>
Signed-off-by: Adalbert Lazăr <ala...@bitdefender.com>
---
Documentation/virt/kvm/kvmi.rst | 8 ++
arch/x86/kvm/Makefile | 2 +-
arch/x86/kvm/kvmi_msg.c | 17 ++++
include/uapi/linux/kvmi.h | 6 ++
virt/kvm/introspection/kvmi_int.h | 16 ++++
virt/kvm/introspection/kvmi_msg.c | 150 +++++++++++++++++++++++++++++-
6 files changed, 196 insertions(+), 3 deletions(-)
create mode 100644 arch/x86/kvm/kvmi_msg.c
diff --git a/Documentation/virt/kvm/kvmi.rst b/Documentation/virt/kvm/kvmi.rst
index c424acf01784..79152f47b30f 100644
--- a/Documentation/virt/kvm/kvmi.rst
+++ b/Documentation/virt/kvm/kvmi.rst
@@ -221,6 +221,14 @@ The following C structures are meant to be used directly
when communicating
over the wire. The peer that detects any size mismatch should simply close
the connection and report the error.
+The vCPU commands start with::
+
+ struct kvmi_vcpu_hdr {
+ __u16 vcpu;
+ __u16 padding1;
+ __u32 padding2;
+ }
+
1. KVMI_GET_VERSION
-------------------
diff --git a/arch/x86/kvm/Makefile b/arch/x86/kvm/Makefile
index af58e1daf7cf..6b2e5f0524e5 100644
--- a/arch/x86/kvm/Makefile
+++ b/arch/x86/kvm/Makefile
@@ -14,7 +14,7 @@ kvm-y += $(KVM)/kvm_main.o
$(KVM)/coalesced_mmio.o \
$(KVM)/eventfd.o $(KVM)/irqchip.o $(KVM)/vfio.o
\
$(KVM)/dirty_ring.o $(KVM)/binary_stats.o
kvm-$(CONFIG_KVM_ASYNC_PF) += $(KVM)/async_pf.o
-kvm-$(CONFIG_KVM_INTROSPECTION) += $(KVMI)/kvmi.o $(KVMI)/kvmi_msg.o kvmi.o
+kvm-$(CONFIG_KVM_INTROSPECTION) += $(KVMI)/kvmi.o $(KVMI)/kvmi_msg.o kvmi.o
kvmi_msg.o
kvm-y += x86.o emulate.o i8259.o irq.o lapic.o \
i8254.o ioapic.o irq_comm.o cpuid.o pmu.o mtrr.o \
diff --git a/arch/x86/kvm/kvmi_msg.c b/arch/x86/kvm/kvmi_msg.c
new file mode 100644
index 000000000000..0a6edfe16f17
--- /dev/null
+++ b/arch/x86/kvm/kvmi_msg.c
@@ -0,0 +1,17 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * KVM introspection (message handling) - x86
+ *
+ * Copyright (C) 2020-2021 Bitdefender S.R.L.
+ *
+ */
+
+#include "../../../virt/kvm/introspection/kvmi_int.h"
+
+static const kvmi_vcpu_msg_job_fct msg_vcpu[] = {
+};
+
+kvmi_vcpu_msg_job_fct kvmi_arch_vcpu_msg_handler(u16 id)
+{
+ return id < ARRAY_SIZE(msg_vcpu) ? msg_vcpu[id] : NULL;
+}
diff --git a/include/uapi/linux/kvmi.h b/include/uapi/linux/kvmi.h
index 048afad01be6..7ba1c8758aba 100644
--- a/include/uapi/linux/kvmi.h
+++ b/include/uapi/linux/kvmi.h
@@ -107,4 +107,10 @@ struct kvmi_vm_write_physical {
__u8 data[0];
};
+struct kvmi_vcpu_hdr {
+ __u16 vcpu;
+ __u16 padding1;
+ __u32 padding2;
+};
+
#endif /* _UAPI__LINUX_KVMI_H */
diff --git a/virt/kvm/introspection/kvmi_int.h
b/virt/kvm/introspection/kvmi_int.h
index c3aa12554c2b..c3e4da7e7f20 100644
--- a/virt/kvm/introspection/kvmi_int.h
+++ b/virt/kvm/introspection/kvmi_int.h
@@ -14,6 +14,18 @@
*/
#define KVMI_MAX_MSG_SIZE (4096 * 2 - sizeof(struct kvmi_msg_hdr))
+struct kvmi_vcpu_msg_job {
+ struct {
+ struct kvmi_msg_hdr hdr;
+ struct kvmi_vcpu_hdr vcpu_hdr;
+ } *msg;
+ struct kvm_vcpu *vcpu;
+};
+
+typedef int (*kvmi_vcpu_msg_job_fct)(const struct kvmi_vcpu_msg_job *job,
+ const struct kvmi_msg_hdr *msg,
+ const void *req);
+
/* kvmi_msg.c */
bool kvmi_sock_get(struct kvm_introspection *kvmi, int fd);
void kvmi_sock_shutdown(struct kvm_introspection *kvmi);
@@ -28,6 +40,9 @@ bool kvmi_is_command_allowed(struct kvm_introspection *kvmi,
u16 id);
bool kvmi_is_event_allowed(struct kvm_introspection *kvmi, u16 id);
bool kvmi_is_known_event(u16 id);
bool kvmi_is_known_vm_event(u16 id);
+int kvmi_add_job(struct kvm_vcpu *vcpu,
+ void (*fct)(struct kvm_vcpu *vcpu, void *ctx),
+ void *ctx, void (*free_fct)(void *ctx));
int kvmi_cmd_vm_control_events(struct kvm_introspection *kvmi,
u16 event_id, bool enable);
int kvmi_cmd_read_physical(struct kvm *kvm, u64 gpa, size_t size,
@@ -40,5 +55,6 @@ int kvmi_cmd_write_physical(struct kvm *kvm, u64 gpa, size_t
size,
/* arch */
void kvmi_arch_init_vcpu_events_mask(unsigned long *supported);
+kvmi_vcpu_msg_job_fct kvmi_arch_vcpu_msg_handler(u16 id);
#endif
diff --git a/virt/kvm/introspection/kvmi_msg.c
b/virt/kvm/introspection/kvmi_msg.c
index 697c307ea745..82e2b49a960e 100644
--- a/virt/kvm/introspection/kvmi_msg.c
+++ b/virt/kvm/introspection/kvmi_msg.c
@@ -13,6 +13,7 @@ typedef int (*kvmi_vm_msg_fct)(struct kvm_introspection *kvmi,
const void *req);
static bool is_vm_command(u16 id);
+static bool is_vcpu_command(u16 id);
bool kvmi_sock_get(struct kvm_introspection *kvmi, int fd)
{
@@ -104,6 +105,17 @@ static int kvmi_msg_vm_reply(struct kvm_introspection
*kvmi,
return kvmi_msg_reply(kvmi, msg, err, rpl, rpl_size);
}
+static struct kvm_vcpu *kvmi_get_vcpu(struct kvm_introspection *kvmi,
+ unsigned int vcpu_idx)
+{
+ struct kvm *kvm = kvmi->kvm;
+
+ if (vcpu_idx >= atomic_read(&kvm->online_vcpus))
+ return NULL;
+
+ return kvm_get_vcpu(kvm, vcpu_idx);
+}
+
static int handle_get_version(struct kvm_introspection *kvmi,
const struct kvmi_msg_hdr *msg, const void *req)
{
@@ -125,7 +137,7 @@ static int handle_vm_check_command(struct kvm_introspection
*kvmi,
if (req->padding1 || req->padding2)
ec = -KVM_EINVAL;
- else if (!is_vm_command(req->id))
+ else if (!is_vm_command(req->id) && !is_vcpu_command(req->id))
ec = -KVM_ENOENT;
else if (!kvmi_is_command_allowed(kvmi, req->id))
ec = -KVM_EPERM;
@@ -254,6 +266,74 @@ static bool is_vm_command(u16 id)
return is_vm_message(id) && id != KVMI_VM_EVENT;
}
+/*
+ * These functions are executed from the vCPU thread. The receiving thread
+ * passes the messages using a newly allocated 'struct kvmi_vcpu_msg_job'
+ * and signals the vCPU to handle the message (which includes
+ * sending back the reply).
+ */
+static const kvmi_vcpu_msg_job_fct msg_vcpu[] = {
+};
+
+static kvmi_vcpu_msg_job_fct get_vcpu_msg_handler(u16 id)
+{
+ kvmi_vcpu_msg_job_fct fct;
+
+ fct = id < ARRAY_SIZE(msg_vcpu) ? msg_vcpu[id] : NULL;
+
+ if (!fct)
+ fct = kvmi_arch_vcpu_msg_handler(id);
+
+ return fct;
+}
+
+static bool is_vcpu_message(u16 id)
+{
+ bool is_vcpu_msg_id = id & 1;
+
+ return is_vcpu_msg_id && !!get_vcpu_msg_handler(id);
+}
+
+static bool is_vcpu_command(u16 id)
+{
+ return is_vcpu_message(id);
+}
+
+static void kvmi_job_vcpu_msg(struct kvm_vcpu *vcpu, void *ctx)
+{
+ struct kvmi_vcpu_msg_job *job = ctx;
+ kvmi_vcpu_msg_job_fct fct;
+ int err;
+
+ job->vcpu = vcpu;
+
+ fct = get_vcpu_msg_handler(job->msg->hdr.id);
+ err = fct(job, &job->msg->hdr, job->msg + 1);
+
+ /*
+ * The soft errors are sent with the reply.
+ * On hard errors, like this one,
+ * we shut down the socket.
+ */
+ if (err)
+ kvmi_sock_shutdown(KVMI(vcpu->kvm));
+}
+
+static void kvmi_free_ctx(void *_ctx)
+{
+ const struct kvmi_vcpu_msg_job *ctx = _ctx;
+
+ kvmi_msg_free(ctx->msg);
+ kfree(ctx);
+}
+
+static int kvmi_msg_queue_to_vcpu(struct kvm_vcpu *vcpu,
+ const struct kvmi_vcpu_msg_job *cmd)
+{
+ return kvmi_add_job(vcpu, kvmi_job_vcpu_msg, (void *)cmd,
+ kvmi_free_ctx);
+}
+
static struct kvmi_msg_hdr *kvmi_msg_recv(struct kvm_introspection *kvmi)
{
struct kvmi_msg_hdr *msg;
@@ -307,9 +387,72 @@ static int kvmi_msg_handle_vm_cmd(struct kvm_introspection
*kvmi,
return kvmi_msg_do_vm_cmd(kvmi, msg);
}
+static bool vcpu_can_handle_messages(struct kvm_vcpu *vcpu)
+{
+ return vcpu->arch.mp_state != KVM_MP_STATE_UNINITIALIZED;
+}
+
+static int kvmi_get_vcpu_if_ready(struct kvm_introspection *kvmi,
+ unsigned int vcpu_idx,
+ struct kvm_vcpu **vcpu)
+{
+ *vcpu = kvmi_get_vcpu(kvmi, vcpu_idx);
+ if (*vcpu == NULL)
+ return -KVM_EINVAL;
+
+ if (!vcpu_can_handle_messages(*vcpu))
+ return -KVM_EAGAIN;
+
+ return 0;
+}
+
+static int kvmi_msg_dispatch_vcpu_msg(struct kvm_introspection *kvmi,
+ struct kvmi_msg_hdr *msg,
+ struct kvm_vcpu *vcpu)
+{
+ struct kvmi_vcpu_msg_job *job_cmd;
+ int err;
+
+ job_cmd = kzalloc(sizeof(*job_cmd), GFP_KERNEL);
+ if (!job_cmd)
+ return -ENOMEM;
+
+ job_cmd->msg = (void *)msg;
+
+ err = kvmi_msg_queue_to_vcpu(vcpu, job_cmd);
+ if (err)
+ kfree(job_cmd);
+
+ return err;
+}
+
+static int kvmi_msg_handle_vcpu_msg(struct kvm_introspection *kvmi,
+ struct kvmi_msg_hdr *msg,
+ bool *queued)
+{
+ struct kvmi_vcpu_hdr *vcpu_hdr = (struct kvmi_vcpu_hdr *)(msg + 1);
+ struct kvm_vcpu *vcpu = NULL;
+ int err, ec;
+
+ if (!kvmi_is_command_allowed(kvmi, msg->id))
+ return kvmi_msg_vm_reply_ec(kvmi, msg, -KVM_EPERM);
+
+ if (vcpu_hdr->padding1 || vcpu_hdr->padding2)
+ return kvmi_msg_vm_reply_ec(kvmi, msg, -KVM_EINVAL);
+
+ ec = kvmi_get_vcpu_if_ready(kvmi, vcpu_hdr->vcpu, &vcpu);
+ if (ec)
+ return kvmi_msg_vm_reply_ec(kvmi, msg, ec);
+
+ err = kvmi_msg_dispatch_vcpu_msg(kvmi, msg, vcpu);
+ *queued = err == 0;
+ return err;
+}
+
bool kvmi_msg_process(struct kvm_introspection *kvmi)
{
struct kvmi_msg_hdr *msg;
+ bool queued = false;
int err = -1;
msg = kvmi_msg_recv(kvmi);
@@ -318,10 +461,13 @@ bool kvmi_msg_process(struct kvm_introspection *kvmi)
if (is_vm_command(msg->id))
err = kvmi_msg_handle_vm_cmd(kvmi, msg);
+ else if (is_vcpu_message(msg->id))
+ err = kvmi_msg_handle_vcpu_msg(kvmi, msg, &queued);
else
err = kvmi_msg_vm_reply_ec(kvmi, msg, -KVM_ENOSYS);
- kvmi_msg_free(msg);
+ if (!queued)
+ kvmi_msg_free(msg);
out:
return err == 0;
}
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