From: Mihai Donțu <mdontu@xxxxxxxxxxxxxxx>
This command is allowed only during a vCPU event (an event has been sent
and the vCPU is waiting for the reply). The registers will be set only
when the reply has been received.
Suggested-by: Paolo Bonzini <pbonzini@xxxxxxxxxx>
Signed-off-by: Mihai Donțu <mdontu@xxxxxxxxxxxxxxx>
Co-developed-by: Mircea Cîrjaliu <mcirjaliu@xxxxxxxxxxxxxxx>
Signed-off-by: Mircea Cîrjaliu <mcirjaliu@xxxxxxxxxxxxxxx>
Signed-off-by: Adalbert Lazăr <alazar@xxxxxxxxxxxxxxx>
---
Documentation/virtual/kvm/kvmi.rst | 28 +++++++++++++++++++++++++
arch/x86/kvm/x86.c | 33 ++++++++++++++++++++++++++++++
include/linux/kvm_host.h | 1 +
virt/kvm/kvmi.c | 25 ++++++++++++++++++++++
virt/kvm/kvmi_int.h | 5 +++++
virt/kvm/kvmi_msg.c | 16 +++++++++++++++
6 files changed, 108 insertions(+)
diff --git a/Documentation/virtual/kvm/kvmi.rst b/Documentation/virtual/kvm/kvmi.rst
index edf81e03ca3c..b6722d071ab7 100644
--- a/Documentation/virtual/kvm/kvmi.rst
+++ b/Documentation/virtual/kvm/kvmi.rst
@@ -905,6 +905,34 @@ registers, the special registers and the requested set of MSRs.
* -KVM_EAGAIN - the selected vCPU can't be introspected yet
* -KVM_ENOMEM - not enough memory to allocate the reply
+18. KVMI_SET_REGISTERS
+----------------------
+
+:Architectures: x86
+:Versions: >= 1
+:Parameters:
+
+::
+
+ struct kvmi_vcpu_hdr;
+ struct kvm_regs;
+
+:Returns:
+
+::
+
+ struct kvmi_error_code
+
+Sets the general purpose registers for the given vCPU. The changes become
+visible to other threads accessing the KVM vCPU structure after the event
+currently being handled is replied to.
+
+:Errors:
+
+* -KVM_EINVAL - the selected vCPU is invalid
+* -KVM_EINVAL - padding is not zero
+* -KVM_EAGAIN - the selected vCPU can't be introspected yet
+
Events
======
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index ef29ef7617bf..62d15bbb2332 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -8431,6 +8431,39 @@ int kvm_arch_vcpu_ioctl_set_regs(struct kvm_vcpu *vcpu, struct kvm_regs *regs)
return 0;
}
+/*
+ * Similar to __set_regs() but it does not reset the exceptions
+ */
+void kvm_arch_vcpu_set_regs(struct kvm_vcpu *vcpu, struct kvm_regs *regs)
+{
+ vcpu->arch.emulate_regs_need_sync_from_vcpu = true;
+ vcpu->arch.emulate_regs_need_sync_to_vcpu = false;
+
+ kvm_register_write(vcpu, VCPU_REGS_RAX, regs->rax);
+ kvm_register_write(vcpu, VCPU_REGS_RBX, regs->rbx);
+ kvm_register_write(vcpu, VCPU_REGS_RCX, regs->rcx);
+ kvm_register_write(vcpu, VCPU_REGS_RDX, regs->rdx);
+ kvm_register_write(vcpu, VCPU_REGS_RSI, regs->rsi);
+ kvm_register_write(vcpu, VCPU_REGS_RDI, regs->rdi);
+ kvm_register_write(vcpu, VCPU_REGS_RSP, regs->rsp);
+ kvm_register_write(vcpu, VCPU_REGS_RBP, regs->rbp);
+#ifdef CONFIG_X86_64
+ kvm_register_write(vcpu, VCPU_REGS_R8, regs->r8);
+ kvm_register_write(vcpu, VCPU_REGS_R9, regs->r9);
+ kvm_register_write(vcpu, VCPU_REGS_R10, regs->r10);
+ kvm_register_write(vcpu, VCPU_REGS_R11, regs->r11);
+ kvm_register_write(vcpu, VCPU_REGS_R12, regs->r12);
+ kvm_register_write(vcpu, VCPU_REGS_R13, regs->r13);
+ kvm_register_write(vcpu, VCPU_REGS_R14, regs->r14);
+ kvm_register_write(vcpu, VCPU_REGS_R15, regs->r15);
+#endif
+
+ kvm_rip_write(vcpu, regs->rip);
+ kvm_set_rflags(vcpu, regs->rflags | X86_EFLAGS_FIXED);
+
+ kvm_make_request(KVM_REQ_EVENT, vcpu);
+}
+
void kvm_get_cs_db_l_bits(struct kvm_vcpu *vcpu, int *db, int *l)
{
struct kvm_segment cs;
diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h
index 09bc06747642..c8eb1a4d997f 100644
--- a/include/linux/kvm_host.h
+++ b/include/linux/kvm_host.h
@@ -791,6 +791,7 @@ int kvm_arch_vcpu_ioctl_translate(struct kvm_vcpu *vcpu,
int kvm_arch_vcpu_ioctl_get_regs(struct kvm_vcpu *vcpu, struct kvm_regs *regs);
void kvm_arch_vcpu_get_regs(struct kvm_vcpu *vcpu, struct kvm_regs *regs);
int kvm_arch_vcpu_ioctl_set_regs(struct kvm_vcpu *vcpu, struct kvm_regs *regs);
+void kvm_arch_vcpu_set_regs(struct kvm_vcpu *vcpu, struct kvm_regs *regs);
int kvm_arch_vcpu_ioctl_get_sregs(struct kvm_vcpu *vcpu,
struct kvm_sregs *sregs);
void kvm_arch_vcpu_get_sregs(struct kvm_vcpu *vcpu,
diff --git a/virt/kvm/kvmi.c b/virt/kvm/kvmi.c
index 85de2da3eb7b..a20891d3a2ce 100644
--- a/virt/kvm/kvmi.c
+++ b/virt/kvm/kvmi.c
@@ -1212,6 +1212,31 @@ void kvmi_handle_requests(struct kvm_vcpu *vcpu)
kvmi_put(vcpu->kvm);
}
+void kvmi_post_reply(struct kvm_vcpu *vcpu)
+{
+ struct kvmi_vcpu *ivcpu = IVCPU(vcpu);
+
+ if (ivcpu->have_delayed_regs) {
+ kvm_arch_vcpu_set_regs(vcpu, &ivcpu->delayed_regs);
+ ivcpu->have_delayed_regs = false;
+ }
+}
+
+int kvmi_cmd_set_registers(struct kvm_vcpu *vcpu, const struct kvm_regs *regs)
+{
+ struct kvmi_vcpu *ivcpu = IVCPU(vcpu);
+
+ if (ivcpu->reply_waiting) {
+ /* defer set registers until we get the reply */
+ memcpy(&ivcpu->delayed_regs, regs, sizeof(ivcpu->delayed_regs));
+ ivcpu->have_delayed_regs = true;
+ } else {
+ kvmi_err(IKVM(vcpu->kvm), "Dropped KVMI_SET_REGISTERS\n");
+ }
+
+ return 0;
+}
+
int kvmi_cmd_get_page_access(struct kvmi *ikvm, u64 gpa, u8 *access)
{
gfn_t gfn = gpa_to_gfn(gpa);
diff --git a/virt/kvm/kvmi_int.h b/virt/kvm/kvmi_int.h
index b547809d13ae..7bc3dd1f2298 100644
--- a/virt/kvm/kvmi_int.h
+++ b/virt/kvm/kvmi_int.h
@@ -105,6 +105,9 @@ struct kvmi_vcpu {
bool reply_waiting;
struct kvmi_vcpu_reply reply;
+ bool have_delayed_regs;
+ struct kvm_regs delayed_regs;
+
DECLARE_BITMAP(ev_mask, KVMI_NUM_EVENTS);
struct list_head job_list;
@@ -173,6 +176,7 @@ int kvmi_msg_send_unhook(struct kvmi *ikvm);
void *kvmi_msg_alloc(void);
void *kvmi_msg_alloc_check(size_t size);
void kvmi_msg_free(void *addr);
+int kvmi_cmd_set_registers(struct kvm_vcpu *vcpu, const struct kvm_regs *regs);
int kvmi_cmd_get_page_access(struct kvmi *ikvm, u64 gpa, u8 *access);
int kvmi_cmd_set_page_access(struct kvmi *ikvm, u64 gpa, u8 access);
int kvmi_cmd_get_page_write_bitmap(struct kvmi *ikvm, u64 gpa, u32 *bitmap);
@@ -190,6 +194,7 @@ 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);
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,
void (*fct)(struct kvm_vcpu *vcpu, void *ctx),
void *ctx, void (*free_fct)(void *ctx));
diff --git a/virt/kvm/kvmi_msg.c b/virt/kvm/kvmi_msg.c
index 9ae0622ff09e..355cec70a28d 100644
--- a/virt/kvm/kvmi_msg.c
+++ b/virt/kvm/kvmi_msg.c
@@ -39,6 +39,7 @@ static const char *const msg_IDs[] = {
[KVMI_READ_PHYSICAL] = "KVMI_READ_PHYSICAL",
[KVMI_SET_PAGE_ACCESS] = "KVMI_SET_PAGE_ACCESS",
[KVMI_SET_PAGE_WRITE_BITMAP] = "KVMI_SET_PAGE_WRITE_BITMAP",
+ [KVMI_SET_REGISTERS] = "KVMI_SET_REGISTERS",
[KVMI_WRITE_PHYSICAL] = "KVMI_WRITE_PHYSICAL",
};
@@ -605,6 +606,19 @@ static int handle_get_registers(struct kvm_vcpu *vcpu,
return err;
}
+static int handle_set_registers(struct kvm_vcpu *vcpu,
+ const struct kvmi_msg_hdr *msg,
+ const void *_req,
+ vcpu_reply_fct reply_cb)
+{
+ const struct kvm_regs *regs = _req;
+ int err;
+
+ err = kvmi_cmd_set_registers(vcpu, regs);
+
+ return reply_cb(vcpu, msg, err, NULL, 0);
+}
+
static int handle_control_events(struct kvm_vcpu *vcpu,
const struct kvmi_msg_hdr *msg,
const void *_req,
@@ -640,6 +654,7 @@ static int(*const msg_vcpu[])(struct kvm_vcpu *,
[KVMI_EVENT_REPLY] = handle_event_reply,
[KVMI_GET_REGISTERS] = handle_get_registers,
[KVMI_GET_VCPU_INFO] = handle_get_vcpu_info,
+ [KVMI_SET_REGISTERS] = handle_set_registers,
};
static void kvmi_job_vcpu_cmd(struct kvm_vcpu *vcpu, void *_ctx)
@@ -937,6 +952,7 @@ int kvmi_send_event(struct kvm_vcpu *vcpu, u32 ev_id,
if (err)
goto out;
+ kvmi_post_reply(vcpu);
*action = ivcpu->reply.action;
out:
