From: Ștefan Șicleru <ssicl...@bitdefender.com>
The introspection tool uses this function to check the hardware support
for EPT switching, which can be used to singlestep vCPUs
on a unprotected EPT view.
Signed-off-by: Ștefan Șicleru <ssicl...@bitdefender.com>
Signed-off-by: Adalbert Lazăr <ala...@bitdefender.com>
---
Documentation/virt/kvm/kvmi.rst | 36 ++++++++++++++++
arch/x86/include/uapi/asm/kvmi.h | 6 +++
arch/x86/kvm/kvmi.c | 9 ++++
include/uapi/linux/kvmi.h | 1 +
.../testing/selftests/kvm/x86_64/kvmi_test.c | 43 +++++++++++++++++++
virt/kvm/introspection/kvmi_int.h | 6 +++
virt/kvm/introspection/kvmi_msg.c | 20 +++++++++
7 files changed, 121 insertions(+)
diff --git a/Documentation/virt/kvm/kvmi.rst b/Documentation/virt/kvm/kvmi.rst
index 76a2d0125f78..02f03c62adef 100644
--- a/Documentation/virt/kvm/kvmi.rst
+++ b/Documentation/virt/kvm/kvmi.rst
@@ -1154,6 +1154,42 @@ be zero.
* -KVM_EINVAL - the padding is not zero
* -KVM_EAGAIN - the selected vCPU can't be introspected yet
+27. KVMI_VCPU_SET_EPT_VIEW
+--------------------------
+
+:Architecture: x86
+:Versions: >= 1
+:Parameters:
+
+::
+
+ struct kvmi_vcpu_hdr;
+ struct kvmi_vcpu_set_ept_view {
+ __u16 view;
+ __u16 padding1;
+ __u32 padding2;
+ };
+
+:Returns:
+
+::
+
+ struct kvmi_error_code;
+
+Configures the vCPU to use the provided ``view``.
+
+Before switching EPT views, the introspection tool should use
+*KVMI_GET_VERSION* to check if the hardware has support for VMFUNC and
+EPTP switching mechanism (see **KVMI_GET_VERSION**).
+
+:Errors:
+
+* -KVM_EINVAL - the selected vCPU is invalid
+* -KVM_EINVAL - padding is not zero
+* -KVM_EINVAL - the selected EPT view is invalid
+* -KVM_EAGAIN - the selected vCPU can't be introspected yet
+* -KVM_EOPNOTSUPP - an EPT view was selected but the hardware doesn't support
it
+
Events
======
diff --git a/arch/x86/include/uapi/asm/kvmi.h b/arch/x86/include/uapi/asm/kvmi.h
index a13a98fa863f..f7a080d5e227 100644
--- a/arch/x86/include/uapi/asm/kvmi.h
+++ b/arch/x86/include/uapi/asm/kvmi.h
@@ -160,4 +160,10 @@ struct kvmi_vcpu_get_ept_view_reply {
__u32 padding2;
};
+struct kvmi_vcpu_set_ept_view {
+ __u16 view;
+ __u16 padding1;
+ __u32 padding2;
+};
+
#endif /* _UAPI_ASM_X86_KVMI_H */
diff --git a/arch/x86/kvm/kvmi.c b/arch/x86/kvm/kvmi.c
index 292606902338..99ea8ef70be2 100644
--- a/arch/x86/kvm/kvmi.c
+++ b/arch/x86/kvm/kvmi.c
@@ -1423,3 +1423,12 @@ u16 kvmi_arch_cmd_get_ept_view(struct kvm_vcpu *vcpu)
{
return kvm_get_ept_view(vcpu);
}
+
+int kvmi_arch_cmd_set_ept_view(struct kvm_vcpu *vcpu, u16 view)
+{
+
+ if (!kvm_x86_ops.set_ept_view)
+ return -KVM_EINVAL;
+
+ return kvm_x86_ops.set_ept_view(vcpu, view);
+}
diff --git a/include/uapi/linux/kvmi.h b/include/uapi/linux/kvmi.h
index cf3422ec60a8..8204661d944d 100644
--- a/include/uapi/linux/kvmi.h
+++ b/include/uapi/linux/kvmi.h
@@ -50,6 +50,7 @@ enum {
KVMI_VCPU_CONTROL_SINGLESTEP = 24,
KVMI_VCPU_TRANSLATE_GVA = 25,
KVMI_VCPU_GET_EPT_VIEW = 26,
+ KVMI_VCPU_SET_EPT_VIEW = 27,
KVMI_NUM_MESSAGES
};
diff --git a/tools/testing/selftests/kvm/x86_64/kvmi_test.c
b/tools/testing/selftests/kvm/x86_64/kvmi_test.c
index 74eafbcae14a..c6f7d10563db 100644
--- a/tools/testing/selftests/kvm/x86_64/kvmi_test.c
+++ b/tools/testing/selftests/kvm/x86_64/kvmi_test.c
@@ -20,6 +20,8 @@
#include "linux/kvm_para.h"
#include "linux/kvmi.h"
+#define KVM_MAX_EPT_VIEWS 3
+
#define VCPU_ID 5
#define X86_FEATURE_XSAVE (1<<26)
@@ -2098,6 +2100,46 @@ static void test_cmd_vcpu_get_ept_view(struct kvm_vm *vm)
pr_info("EPT view %u\n", view);
}
+static void set_ept_view(struct kvm_vm *vm, __u16 view)
+{
+ struct {
+ struct kvmi_msg_hdr hdr;
+ struct kvmi_vcpu_hdr vcpu_hdr;
+ struct kvmi_vcpu_set_ept_view cmd;
+ } req = {};
+
+ req.cmd.view = view;
+
+ test_vcpu0_command(vm, KVMI_VCPU_SET_EPT_VIEW,
+ &req.hdr, sizeof(req), NULL, 0);
+}
+
+static void test_cmd_vcpu_set_ept_view(struct kvm_vm *vm)
+{
+ __u16 old_view;
+ __u16 new_view;
+ __u16 check_view;
+
+ if (!features.eptp) {
+ print_skip("EPT views not supported");
+ return;
+ }
+
+ old_view = get_ept_view(vm);
+
+ new_view = (old_view + 1) % KVM_MAX_EPT_VIEWS;
+ pr_info("Change EPT view from %u to %u\n", old_view, new_view);
+ set_ept_view(vm, new_view);
+
+ check_view = get_ept_view(vm);
+ TEST_ASSERT(check_view == new_view,
+ "Switching EPT view failed, found ept view (%u),
expected view (%u)\n",
+ check_view, new_view);
+
+ pr_info("Change EPT view from %u to %u\n", check_view, old_view);
+ set_ept_view(vm, old_view);
+}
+
static void test_introspection(struct kvm_vm *vm)
{
srandom(time(0));
@@ -2135,6 +2177,7 @@ static void test_introspection(struct kvm_vm *vm)
test_cmd_vcpu_control_singlestep(vm);
test_cmd_translate_gva(vm);
test_cmd_vcpu_get_ept_view(vm);
+ test_cmd_vcpu_set_ept_view(vm);
unhook_introspection(vm);
}
diff --git a/virt/kvm/introspection/kvmi_int.h
b/virt/kvm/introspection/kvmi_int.h
index f88999bf59e8..f093aad2f804 100644
--- a/virt/kvm/introspection/kvmi_int.h
+++ b/virt/kvm/introspection/kvmi_int.h
@@ -32,6 +32,11 @@ static inline bool is_event_enabled(struct kvm_vcpu *vcpu,
int event)
return test_bit(event, VCPUI(vcpu)->ev_enable_mask);
}
+static inline bool is_valid_view(unsigned short view)
+{
+ return (view < KVM_MAX_EPT_VIEWS);
+}
+
/* kvmi_msg.c */
bool kvmi_sock_get(struct kvm_introspection *kvmi, int fd);
void kvmi_sock_shutdown(struct kvm_introspection *kvmi);
@@ -143,5 +148,6 @@ bool kvmi_arch_start_singlestep(struct kvm_vcpu *vcpu);
bool kvmi_arch_stop_singlestep(struct kvm_vcpu *vcpu);
gpa_t kvmi_arch_cmd_translate_gva(struct kvm_vcpu *vcpu, gva_t gva);
u16 kvmi_arch_cmd_get_ept_view(struct kvm_vcpu *vcpu);
+int kvmi_arch_cmd_set_ept_view(struct kvm_vcpu *vcpu, u16 view);
#endif
diff --git a/virt/kvm/introspection/kvmi_msg.c
b/virt/kvm/introspection/kvmi_msg.c
index 6cb3473190db..73a7179f7031 100644
--- a/virt/kvm/introspection/kvmi_msg.c
+++ b/virt/kvm/introspection/kvmi_msg.c
@@ -674,6 +674,25 @@ static int handle_vcpu_get_ept_view(const struct
kvmi_vcpu_msg_job *job,
return kvmi_msg_vcpu_reply(job, msg, 0, &rpl, sizeof(rpl));
}
+static int handle_vcpu_set_ept_view(const struct kvmi_vcpu_msg_job *job,
+ const struct kvmi_msg_hdr *msg,
+ const void *_req)
+{
+ const struct kvmi_vcpu_set_ept_view *req = _req;
+ int ec;
+
+ if (req->padding1 || req->padding2)
+ ec = -KVM_EINVAL;
+ else if (!is_valid_view(req->view))
+ ec = -KVM_EINVAL;
+ else if (!kvm_eptp_switching_supported)
+ ec = -KVM_EOPNOTSUPP;
+ else
+ ec = kvmi_arch_cmd_set_ept_view(job->vcpu, req->view);
+
+ return kvmi_msg_vcpu_reply(job, msg, ec, NULL, 0);
+}
+
/*
* These functions are executed from the vCPU thread. The receiving thread
* passes the messages using a newly allocated 'struct kvmi_vcpu_msg_job'
@@ -695,6 +714,7 @@ static int(*const msg_vcpu[])(const struct
kvmi_vcpu_msg_job *,
[KVMI_VCPU_GET_XCR] = handle_vcpu_get_xcr,
[KVMI_VCPU_GET_XSAVE] = handle_vcpu_get_xsave,
[KVMI_VCPU_INJECT_EXCEPTION] = handle_vcpu_inject_exception,
+ [KVMI_VCPU_SET_EPT_VIEW] = handle_vcpu_set_ept_view,
[KVMI_VCPU_SET_REGISTERS] = handle_vcpu_set_registers,
[KVMI_VCPU_SET_XSAVE] = handle_vcpu_set_xsave,
[KVMI_VCPU_TRANSLATE_GVA] = handle_vcpu_translate_gva,
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