Re: [PATCH v4 2/3] selftests: KVM: AMD Nested test infrastructure

From: Krish Sadhukhan
Date: Thu Feb 06 2020 - 17:58:20 EST




On 02/06/2020 02:47 AM, Eric Auger wrote:
Add the basic infrastructure needed to test AMD nested SVM.
This is largely copied from the KVM unit test infrastructure.

Signed-off-by: Eric Auger <eric.auger@xxxxxxxxxx>

---

v3 -> v4:
- just keep the 16 GPRs in gpr64_regs struct
- vm* instructions do not take any param
- add comments

v2 -> v3:
- s/regs/gp_regs64
- Split the header into 2 parts: svm.h is a copy of
arch/x86/include/asm/svm.h whereas svm_util.h contains
testing add-ons
- use get_gdt/dt() and remove sgdt/sidt
- use get_es/ss/ds/cs
- fix clobber for dr6 & dr7
- use u64 instead of ulong
---
tools/testing/selftests/kvm/Makefile | 2 +-
.../selftests/kvm/include/x86_64/processor.h | 20 ++
.../selftests/kvm/include/x86_64/svm.h | 297 ++++++++++++++++++
.../selftests/kvm/include/x86_64/svm_util.h | 38 +++
tools/testing/selftests/kvm/lib/x86_64/svm.c | 161 ++++++++++
5 files changed, 517 insertions(+), 1 deletion(-)
create mode 100644 tools/testing/selftests/kvm/include/x86_64/svm.h
create mode 100644 tools/testing/selftests/kvm/include/x86_64/svm_util.h
create mode 100644 tools/testing/selftests/kvm/lib/x86_64/svm.c

diff --git a/tools/testing/selftests/kvm/Makefile b/tools/testing/selftests/kvm/Makefile
index 608fa835c764..2e770f554cae 100644
--- a/tools/testing/selftests/kvm/Makefile
+++ b/tools/testing/selftests/kvm/Makefile
@@ -8,7 +8,7 @@ KSFT_KHDR_INSTALL := 1
UNAME_M := $(shell uname -m)
LIBKVM = lib/assert.c lib/elf.c lib/io.c lib/kvm_util.c lib/sparsebit.c
-LIBKVM_x86_64 = lib/x86_64/processor.c lib/x86_64/vmx.c lib/x86_64/ucall.c
+LIBKVM_x86_64 = lib/x86_64/processor.c lib/x86_64/vmx.c lib/x86_64/svm.c lib/x86_64/ucall.c
LIBKVM_aarch64 = lib/aarch64/processor.c lib/aarch64/ucall.c
LIBKVM_s390x = lib/s390x/processor.c lib/s390x/ucall.c
diff --git a/tools/testing/selftests/kvm/include/x86_64/processor.h b/tools/testing/selftests/kvm/include/x86_64/processor.h
index 6f7fffaea2e8..12475047869f 100644
--- a/tools/testing/selftests/kvm/include/x86_64/processor.h
+++ b/tools/testing/selftests/kvm/include/x86_64/processor.h
@@ -56,6 +56,26 @@ enum x86_register {
R15,
};
+/* General Registers in 64-Bit Mode */
+struct gpr64_regs {
+ u64 rax;
+ u64 rcx;
+ u64 rdx;
+ u64 rbx;
+ u64 rsp;
+ u64 rbp;
+ u64 rsi;
+ u64 rdi;
+ u64 r8;
+ u64 r9;
+ u64 r10;
+ u64 r11;
+ u64 r12;
+ u64 r13;
+ u64 r14;
+ u64 r15;
+};
+
struct desc64 {
uint16_t limit0;
uint16_t base0;
diff --git a/tools/testing/selftests/kvm/include/x86_64/svm.h b/tools/testing/selftests/kvm/include/x86_64/svm.h
new file mode 100644
index 000000000000..f4ea2355dbc2
--- /dev/null
+++ b/tools/testing/selftests/kvm/include/x86_64/svm.h
@@ -0,0 +1,297 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * tools/testing/selftests/kvm/include/x86_64/svm.h
+ * This is a copy of arch/x86/include/asm/svm.h
+ *
+ */
+
+#ifndef SELFTEST_KVM_SVM_H
+#define SELFTEST_KVM_SVM_H
+
+enum {
+ INTERCEPT_INTR,
+ INTERCEPT_NMI,
+ INTERCEPT_SMI,
+ INTERCEPT_INIT,
+ INTERCEPT_VINTR,
+ INTERCEPT_SELECTIVE_CR0,
+ INTERCEPT_STORE_IDTR,
+ INTERCEPT_STORE_GDTR,
+ INTERCEPT_STORE_LDTR,
+ INTERCEPT_STORE_TR,
+ INTERCEPT_LOAD_IDTR,
+ INTERCEPT_LOAD_GDTR,
+ INTERCEPT_LOAD_LDTR,
+ INTERCEPT_LOAD_TR,
+ INTERCEPT_RDTSC,
+ INTERCEPT_RDPMC,
+ INTERCEPT_PUSHF,
+ INTERCEPT_POPF,
+ INTERCEPT_CPUID,
+ INTERCEPT_RSM,
+ INTERCEPT_IRET,
+ INTERCEPT_INTn,
+ INTERCEPT_INVD,
+ INTERCEPT_PAUSE,
+ INTERCEPT_HLT,
+ INTERCEPT_INVLPG,
+ INTERCEPT_INVLPGA,
+ INTERCEPT_IOIO_PROT,
+ INTERCEPT_MSR_PROT,
+ INTERCEPT_TASK_SWITCH,
+ INTERCEPT_FERR_FREEZE,
+ INTERCEPT_SHUTDOWN,
+ INTERCEPT_VMRUN,
+ INTERCEPT_VMMCALL,
+ INTERCEPT_VMLOAD,
+ INTERCEPT_VMSAVE,
+ INTERCEPT_STGI,
+ INTERCEPT_CLGI,
+ INTERCEPT_SKINIT,
+ INTERCEPT_RDTSCP,
+ INTERCEPT_ICEBP,
+ INTERCEPT_WBINVD,
+ INTERCEPT_MONITOR,
+ INTERCEPT_MWAIT,
+ INTERCEPT_MWAIT_COND,
+ INTERCEPT_XSETBV,
+ INTERCEPT_RDPRU,
+};
+
+
+struct __attribute__ ((__packed__)) vmcb_control_area {
+ u32 intercept_cr;
+ u32 intercept_dr;
+ u32 intercept_exceptions;
+ u64 intercept;
+ u8 reserved_1[40];
+ u16 pause_filter_thresh;
+ u16 pause_filter_count;
+ u64 iopm_base_pa;
+ u64 msrpm_base_pa;
+ u64 tsc_offset;
+ u32 asid;
+ u8 tlb_ctl;
+ u8 reserved_2[3];
+ u32 int_ctl;
+ u32 int_vector;
+ u32 int_state;
+ u8 reserved_3[4];
+ u32 exit_code;
+ u32 exit_code_hi;
+ u64 exit_info_1;
+ u64 exit_info_2;
+ u32 exit_int_info;
+ u32 exit_int_info_err;
+ u64 nested_ctl;
+ u64 avic_vapic_bar;
+ u8 reserved_4[8];
+ u32 event_inj;
+ u32 event_inj_err;
+ u64 nested_cr3;
+ u64 virt_ext;
+ u32 clean;
+ u32 reserved_5;
+ u64 next_rip;
+ u8 insn_len;
+ u8 insn_bytes[15];
+ u64 avic_backing_page; /* Offset 0xe0 */
+ u8 reserved_6[8]; /* Offset 0xe8 */
+ u64 avic_logical_id; /* Offset 0xf0 */
+ u64 avic_physical_id; /* Offset 0xf8 */
+ u8 reserved_7[768];
+};
+
+
+#define TLB_CONTROL_DO_NOTHING 0
+#define TLB_CONTROL_FLUSH_ALL_ASID 1
+#define TLB_CONTROL_FLUSH_ASID 3
+#define TLB_CONTROL_FLUSH_ASID_LOCAL 7
+
+#define V_TPR_MASK 0x0f
+
+#define V_IRQ_SHIFT 8
+#define V_IRQ_MASK (1 << V_IRQ_SHIFT)
+
+#define V_GIF_SHIFT 9
+#define V_GIF_MASK (1 << V_GIF_SHIFT)
+
+#define V_INTR_PRIO_SHIFT 16
+#define V_INTR_PRIO_MASK (0x0f << V_INTR_PRIO_SHIFT)
+
+#define V_IGN_TPR_SHIFT 20
+#define V_IGN_TPR_MASK (1 << V_IGN_TPR_SHIFT)
+
+#define V_INTR_MASKING_SHIFT 24
+#define V_INTR_MASKING_MASK (1 << V_INTR_MASKING_SHIFT)
+
+#define V_GIF_ENABLE_SHIFT 25
+#define V_GIF_ENABLE_MASK (1 << V_GIF_ENABLE_SHIFT)
+
+#define AVIC_ENABLE_SHIFT 31
+#define AVIC_ENABLE_MASK (1 << AVIC_ENABLE_SHIFT)
+
+#define LBR_CTL_ENABLE_MASK BIT_ULL(0)
+#define VIRTUAL_VMLOAD_VMSAVE_ENABLE_MASK BIT_ULL(1)
+
+#define SVM_INTERRUPT_SHADOW_MASK 1
+
+#define SVM_IOIO_STR_SHIFT 2
+#define SVM_IOIO_REP_SHIFT 3
+#define SVM_IOIO_SIZE_SHIFT 4
+#define SVM_IOIO_ASIZE_SHIFT 7
+
+#define SVM_IOIO_TYPE_MASK 1
+#define SVM_IOIO_STR_MASK (1 << SVM_IOIO_STR_SHIFT)
+#define SVM_IOIO_REP_MASK (1 << SVM_IOIO_REP_SHIFT)
+#define SVM_IOIO_SIZE_MASK (7 << SVM_IOIO_SIZE_SHIFT)
+#define SVM_IOIO_ASIZE_MASK (7 << SVM_IOIO_ASIZE_SHIFT)
+
+#define SVM_VM_CR_VALID_MASK 0x001fULL
+#define SVM_VM_CR_SVM_LOCK_MASK 0x0008ULL
+#define SVM_VM_CR_SVM_DIS_MASK 0x0010ULL
+
+#define SVM_NESTED_CTL_NP_ENABLE BIT(0)
+#define SVM_NESTED_CTL_SEV_ENABLE BIT(1)
+
+struct __attribute__ ((__packed__)) vmcb_seg {
+ u16 selector;
+ u16 attrib;
+ u32 limit;
+ u64 base;
+};
+
+struct __attribute__ ((__packed__)) vmcb_save_area {
+ struct vmcb_seg es;
+ struct vmcb_seg cs;
+ struct vmcb_seg ss;
+ struct vmcb_seg ds;
+ struct vmcb_seg fs;
+ struct vmcb_seg gs;
+ struct vmcb_seg gdtr;
+ struct vmcb_seg ldtr;
+ struct vmcb_seg idtr;
+ struct vmcb_seg tr;
+ u8 reserved_1[43];
+ u8 cpl;
+ u8 reserved_2[4];
+ u64 efer;
+ u8 reserved_3[112];
+ u64 cr4;
+ u64 cr3;
+ u64 cr0;
+ u64 dr7;
+ u64 dr6;
+ u64 rflags;
+ u64 rip;
+ u8 reserved_4[88];
+ u64 rsp;
+ u8 reserved_5[24];
+ u64 rax;
+ u64 star;
+ u64 lstar;
+ u64 cstar;
+ u64 sfmask;
+ u64 kernel_gs_base;
+ u64 sysenter_cs;
+ u64 sysenter_esp;
+ u64 sysenter_eip;
+ u64 cr2;
+ u8 reserved_6[32];
+ u64 g_pat;
+ u64 dbgctl;
+ u64 br_from;
+ u64 br_to;
+ u64 last_excp_from;
+ u64 last_excp_to;
+};
+
+struct __attribute__ ((__packed__)) vmcb {
+ struct vmcb_control_area control;
+ struct vmcb_save_area save;
+};
+
+#define SVM_CPUID_FUNC 0x8000000a
+
+#define SVM_VM_CR_SVM_DISABLE 4
+
+#define SVM_SELECTOR_S_SHIFT 4
+#define SVM_SELECTOR_DPL_SHIFT 5
+#define SVM_SELECTOR_P_SHIFT 7
+#define SVM_SELECTOR_AVL_SHIFT 8
+#define SVM_SELECTOR_L_SHIFT 9
+#define SVM_SELECTOR_DB_SHIFT 10
+#define SVM_SELECTOR_G_SHIFT 11
+
+#define SVM_SELECTOR_TYPE_MASK (0xf)
+#define SVM_SELECTOR_S_MASK (1 << SVM_SELECTOR_S_SHIFT)
+#define SVM_SELECTOR_DPL_MASK (3 << SVM_SELECTOR_DPL_SHIFT)
+#define SVM_SELECTOR_P_MASK (1 << SVM_SELECTOR_P_SHIFT)
+#define SVM_SELECTOR_AVL_MASK (1 << SVM_SELECTOR_AVL_SHIFT)
+#define SVM_SELECTOR_L_MASK (1 << SVM_SELECTOR_L_SHIFT)
+#define SVM_SELECTOR_DB_MASK (1 << SVM_SELECTOR_DB_SHIFT)
+#define SVM_SELECTOR_G_MASK (1 << SVM_SELECTOR_G_SHIFT)
+
+#define SVM_SELECTOR_WRITE_MASK (1 << 1)
+#define SVM_SELECTOR_READ_MASK SVM_SELECTOR_WRITE_MASK
+#define SVM_SELECTOR_CODE_MASK (1 << 3)
+
+#define INTERCEPT_CR0_READ 0
+#define INTERCEPT_CR3_READ 3
+#define INTERCEPT_CR4_READ 4
+#define INTERCEPT_CR8_READ 8
+#define INTERCEPT_CR0_WRITE (16 + 0)
+#define INTERCEPT_CR3_WRITE (16 + 3)
+#define INTERCEPT_CR4_WRITE (16 + 4)
+#define INTERCEPT_CR8_WRITE (16 + 8)
+
+#define INTERCEPT_DR0_READ 0
+#define INTERCEPT_DR1_READ 1
+#define INTERCEPT_DR2_READ 2
+#define INTERCEPT_DR3_READ 3
+#define INTERCEPT_DR4_READ 4
+#define INTERCEPT_DR5_READ 5
+#define INTERCEPT_DR6_READ 6
+#define INTERCEPT_DR7_READ 7
+#define INTERCEPT_DR0_WRITE (16 + 0)
+#define INTERCEPT_DR1_WRITE (16 + 1)
+#define INTERCEPT_DR2_WRITE (16 + 2)
+#define INTERCEPT_DR3_WRITE (16 + 3)
+#define INTERCEPT_DR4_WRITE (16 + 4)
+#define INTERCEPT_DR5_WRITE (16 + 5)
+#define INTERCEPT_DR6_WRITE (16 + 6)
+#define INTERCEPT_DR7_WRITE (16 + 7)
+
+#define SVM_EVTINJ_VEC_MASK 0xff
+
+#define SVM_EVTINJ_TYPE_SHIFT 8
+#define SVM_EVTINJ_TYPE_MASK (7 << SVM_EVTINJ_TYPE_SHIFT)
+
+#define SVM_EVTINJ_TYPE_INTR (0 << SVM_EVTINJ_TYPE_SHIFT)
+#define SVM_EVTINJ_TYPE_NMI (2 << SVM_EVTINJ_TYPE_SHIFT)
+#define SVM_EVTINJ_TYPE_EXEPT (3 << SVM_EVTINJ_TYPE_SHIFT)
+#define SVM_EVTINJ_TYPE_SOFT (4 << SVM_EVTINJ_TYPE_SHIFT)
+
+#define SVM_EVTINJ_VALID (1 << 31)
+#define SVM_EVTINJ_VALID_ERR (1 << 11)
+
+#define SVM_EXITINTINFO_VEC_MASK SVM_EVTINJ_VEC_MASK
+#define SVM_EXITINTINFO_TYPE_MASK SVM_EVTINJ_TYPE_MASK
+
+#define SVM_EXITINTINFO_TYPE_INTR SVM_EVTINJ_TYPE_INTR
+#define SVM_EXITINTINFO_TYPE_NMI SVM_EVTINJ_TYPE_NMI
+#define SVM_EXITINTINFO_TYPE_EXEPT SVM_EVTINJ_TYPE_EXEPT
+#define SVM_EXITINTINFO_TYPE_SOFT SVM_EVTINJ_TYPE_SOFT
+
+#define SVM_EXITINTINFO_VALID SVM_EVTINJ_VALID
+#define SVM_EXITINTINFO_VALID_ERR SVM_EVTINJ_VALID_ERR
+
+#define SVM_EXITINFOSHIFT_TS_REASON_IRET 36
+#define SVM_EXITINFOSHIFT_TS_REASON_JMP 38
+#define SVM_EXITINFOSHIFT_TS_HAS_ERROR_CODE 44
+
+#define SVM_EXITINFO_REG_MASK 0x0F
+
+#define SVM_CR0_SELECTIVE_MASK (X86_CR0_TS | X86_CR0_MP)
+
+#endif /* SELFTEST_KVM_SVM_H */
diff --git a/tools/testing/selftests/kvm/include/x86_64/svm_util.h b/tools/testing/selftests/kvm/include/x86_64/svm_util.h
new file mode 100644
index 000000000000..cd037917fece
--- /dev/null
+++ b/tools/testing/selftests/kvm/include/x86_64/svm_util.h
@@ -0,0 +1,38 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+/*
+ * tools/testing/selftests/kvm/include/x86_64/svm_utils.h
+ * Header for nested SVM testing
+ *
+ * Copyright (C) 2020, Red Hat, Inc.
+ */
+
+#ifndef SELFTEST_KVM_SVM_UTILS_H
+#define SELFTEST_KVM_SVM_UTILS_H
+
+#include <stdint.h>
+#include "svm.h"
+#include "processor.h"
+
+#define CPUID_SVM_BIT 2
+#define CPUID_SVM BIT_ULL(CPUID_SVM_BIT)
+
+#define SVM_EXIT_VMMCALL 0x081
+
+struct svm_test_data {
+ /* VMCB */
+ struct vmcb *vmcb; /* gva */
+ void *vmcb_hva;
+ uint64_t vmcb_gpa;
+
+ /* host state-save area */
+ struct vmcb_save_area *save_area; /* gva */
+ void *save_area_hva;
+ uint64_t save_area_gpa;
+};
Looks like vmcb_hva and save_area_hva haven't been used anywhere. Do we need them ?
+
+struct svm_test_data *vcpu_alloc_svm(struct kvm_vm *vm, vm_vaddr_t *p_svm_gva);
+void generic_svm_setup(struct svm_test_data *svm, void *guest_rip, void *guest_rsp);
+void run_guest(struct vmcb *vmcb, uint64_t vmcb_gpa);
+void nested_svm_check_supported(void);
+
+#endif /* SELFTEST_KVM_SVM_UTILS_H */
diff --git a/tools/testing/selftests/kvm/lib/x86_64/svm.c b/tools/testing/selftests/kvm/lib/x86_64/svm.c
new file mode 100644
index 000000000000..6e05a8fc3fe0
--- /dev/null
+++ b/tools/testing/selftests/kvm/lib/x86_64/svm.c
@@ -0,0 +1,161 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * tools/testing/selftests/kvm/lib/x86_64/svm.c
+ * Helpers used for nested SVM testing
+ * Largely inspired from KVM unit test svm.c
+ *
+ * Copyright (C) 2020, Red Hat, Inc.
+ */
+
+#include "test_util.h"
+#include "kvm_util.h"
+#include "../kvm_util_internal.h"
+#include "processor.h"
+#include "svm_util.h"
+
+struct gpr64_regs guest_regs;
+u64 rflags;
+
+/* Allocate memory regions for nested SVM tests.
+ *
+ * Input Args:
+ * vm - The VM to allocate guest-virtual addresses in.
+ *
+ * Output Args:
+ * p_svm_gva - The guest virtual address for the struct svm_test_data.
+ *
+ * Return:
+ * Pointer to structure with the addresses of the SVM areas.
+ */
+struct svm_test_data *
+vcpu_alloc_svm(struct kvm_vm *vm, vm_vaddr_t *p_svm_gva)
+{
+ vm_vaddr_t svm_gva = vm_vaddr_alloc(vm, getpagesize(),
+ 0x10000, 0, 0);
+ struct svm_test_data *svm = addr_gva2hva(vm, svm_gva);
+
+ svm->vmcb = (void *)vm_vaddr_alloc(vm, getpagesize(),
+ 0x10000, 0, 0);
+ svm->vmcb_hva = addr_gva2hva(vm, (uintptr_t)svm->vmcb);
+ svm->vmcb_gpa = addr_gva2gpa(vm, (uintptr_t)svm->vmcb);
+
+ svm->save_area = (void *)vm_vaddr_alloc(vm, getpagesize(),
+ 0x10000, 0, 0);
+ svm->save_area_hva = addr_gva2hva(vm, (uintptr_t)svm->save_area);
+ svm->save_area_gpa = addr_gva2gpa(vm, (uintptr_t)svm->save_area);
+
+ *p_svm_gva = svm_gva;
+ return svm;
+}
+
+static void vmcb_set_seg(struct vmcb_seg *seg, u16 selector,
+ u64 base, u32 limit, u32 attr)
+{
+ seg->selector = selector;
+ seg->attrib = attr;
+ seg->limit = limit;
+ seg->base = base;
+}
+
+void generic_svm_setup(struct svm_test_data *svm, void *guest_rip, void *guest_rsp)
+{
+ struct vmcb *vmcb = svm->vmcb;
+ uint64_t vmcb_gpa = svm->vmcb_gpa;
+ struct vmcb_save_area *save = &vmcb->save;
+ struct vmcb_control_area *ctrl = &vmcb->control;
+ u32 data_seg_attr = 3 | SVM_SELECTOR_S_MASK | SVM_SELECTOR_P_MASK
+ | SVM_SELECTOR_DB_MASK | SVM_SELECTOR_G_MASK;
+ u32 code_seg_attr = 9 | SVM_SELECTOR_S_MASK | SVM_SELECTOR_P_MASK
+ | SVM_SELECTOR_L_MASK | SVM_SELECTOR_G_MASK;
+ uint64_t efer;
+
+ efer = rdmsr(MSR_EFER);
+ wrmsr(MSR_EFER, efer | EFER_SVME);
+ wrmsr(MSR_VM_HSAVE_PA, svm->save_area_gpa);
+
+ memset(vmcb, 0, sizeof(*vmcb));
+ asm volatile ("vmsave\n\t" : : "a" (vmcb_gpa) : "memory");
+ vmcb_set_seg(&save->es, get_es(), 0, -1U, data_seg_attr);
+ vmcb_set_seg(&save->cs, get_cs(), 0, -1U, code_seg_attr);
+ vmcb_set_seg(&save->ss, get_ss(), 0, -1U, data_seg_attr);
+ vmcb_set_seg(&save->ds, get_ds(), 0, -1U, data_seg_attr);
+ vmcb_set_seg(&save->gdtr, 0, get_gdt().address, get_gdt().size, 0);
+ vmcb_set_seg(&save->idtr, 0, get_idt().address, get_idt().size, 0);
+
+ ctrl->asid = 1;
+ save->cpl = 0;
+ save->efer = rdmsr(MSR_EFER);
+ asm volatile ("mov %%cr4, %0" : "=r"(save->cr4) : : "memory");
+ asm volatile ("mov %%cr3, %0" : "=r"(save->cr3) : : "memory");
+ asm volatile ("mov %%cr0, %0" : "=r"(save->cr0) : : "memory");
+ asm volatile ("mov %%dr7, %0" : "=r"(save->dr7) : : "memory");
+ asm volatile ("mov %%dr6, %0" : "=r"(save->dr6) : : "memory");
+ asm volatile ("mov %%cr2, %0" : "=r"(save->cr2) : : "memory");
+ save->g_pat = rdmsr(MSR_IA32_CR_PAT);
+ save->dbgctl = rdmsr(MSR_IA32_DEBUGCTLMSR);
+ ctrl->intercept = (1ULL << INTERCEPT_VMRUN) |
+ (1ULL << INTERCEPT_VMMCALL);
+
+ vmcb->save.rip = (u64)guest_rip;
+ vmcb->save.rsp = (u64)guest_rsp;
+ guest_regs.rdi = (u64)svm;
+}
+
+/*
+ * save/restore 64-bit general registers except rax, rip, rsp
+ * which are directly handed through the VMCB guest processor state
+ */
+#define SAVE_GPR_C \
+ "xchg %%rbx, guest_regs+0x20\n\t" \
+ "xchg %%rcx, guest_regs+0x10\n\t" \
+ "xchg %%rdx, guest_regs+0x18\n\t" \
+ "xchg %%rbp, guest_regs+0x30\n\t" \
+ "xchg %%rsi, guest_regs+0x38\n\t" \
+ "xchg %%rdi, guest_regs+0x40\n\t" \
+ "xchg %%r8, guest_regs+0x48\n\t" \
+ "xchg %%r9, guest_regs+0x50\n\t" \
+ "xchg %%r10, guest_regs+0x58\n\t" \
+ "xchg %%r11, guest_regs+0x60\n\t" \
+ "xchg %%r12, guest_regs+0x68\n\t" \
+ "xchg %%r13, guest_regs+0x70\n\t" \
+ "xchg %%r14, guest_regs+0x78\n\t" \
+ "xchg %%r15, guest_regs+0x80\n\t"
+
+#define LOAD_GPR_C SAVE_GPR_C
+
+/*
+ * selftests do not use interrupts so we dropped clgi/sti/cli/stgi
+ * for now. registers involved in LOAD/SAVE_GPR_C are eventually
+ * unmodified so they do not need to be in the clobber list.
+ */
+void run_guest(struct vmcb *vmcb, uint64_t vmcb_gpa)
+{
+ asm volatile (
+ "vmload\n\t"
Don't we need to set %rax before calling vmload ?

ÂÂÂÂÂÂÂÂÂÂÂ "mov %[vmcb_gpa], %%rax \n\t"
ÂÂÂÂÂÂÂÂÂÂÂ "vmload %%rax\n\t"

+ "mov rflags, %%r15\n\t" // rflags
+ "mov %%r15, 0x170(%[vmcb])\n\t"
+ "mov guest_regs, %%r15\n\t" // rax
+ "mov %%r15, 0x1f8(%[vmcb])\n\t"
+ LOAD_GPR_C
+ "vmrun\n\t"
+ SAVE_GPR_C
+ "mov 0x170(%[vmcb]), %%r15\n\t" // rflags
+ "mov %%r15, rflags\n\t"
+ "mov 0x1f8(%[vmcb]), %%r15\n\t" // rax
+ "mov %%r15, guest_regs\n\t"
+ "vmsave\n\t"
+ : : [vmcb] "r" (vmcb), [vmcb_gpa] "a" (vmcb_gpa)
+ : "r15", "memory");
+}
+
+void nested_svm_check_supported(void)
+{
+ struct kvm_cpuid_entry2 *entry =
+ kvm_get_supported_cpuid_entry(0x80000001);
+
+ if (!(entry->ecx & CPUID_SVM)) {
+ fprintf(stderr, "nested SVM not enabled, skipping test\n");
I think a better message would be:

ÂÂÂ "nested SVM not supported on this CPU, skipping test\n"

Also, the function should ideally return a boolean and let the callers print whatever they want.

+ exit(KSFT_SKIP);
+ }
+}
+