Re: [PATCH v2 2/8] KVM: x86: move SMM entry to a new file

[Maxim Levitsky <mlevitsk@redhat.com>]

On Thu, 2022-09-29 at 13:20 -0400, Paolo Bonzini wrote:
> Some users of KVM implement the UEFI variable store through a paravirtual
> device that does not require the "SMM lockbox" component of edk2, and
> would like to compile out system management mode.  In preparation for
> that, move the SMM entry code out of x86.c and into a new file.
> 
> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
> ---
>  arch/x86/include/asm/kvm_host.h |   1 +
>  arch/x86/kvm/smm.c              | 235 +++++++++++++++++++++++++++++++
>  arch/x86/kvm/smm.h              |   1 +
>  arch/x86/kvm/x86.c              | 239 +-------------------------------
>  4 files changed, 239 insertions(+), 237 deletions(-)
> 
> diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
> index 0ca8f28854ab..b7d078cd768d 100644
> --- a/arch/x86/include/asm/kvm_host.h
> +++ b/arch/x86/include/asm/kvm_host.h
> @@ -1838,6 +1838,7 @@ int kvm_emulate_ap_reset_hold(struct kvm_vcpu *vcpu);
>  int kvm_emulate_wbinvd(struct kvm_vcpu *vcpu);
>  
>  void kvm_get_segment(struct kvm_vcpu *vcpu, struct kvm_segment *var, int seg);
> +void kvm_set_segment(struct kvm_vcpu *vcpu, struct kvm_segment *var, int seg);
>  int kvm_load_segment_descriptor(struct kvm_vcpu *vcpu, u16 selector, int seg);
>  void kvm_vcpu_deliver_sipi_vector(struct kvm_vcpu *vcpu, u8 vector);
>  
> diff --git a/arch/x86/kvm/smm.c b/arch/x86/kvm/smm.c
> index b91c48d91f6e..26a6859e421f 100644
> --- a/arch/x86/kvm/smm.c
> +++ b/arch/x86/kvm/smm.c
> @@ -5,6 +5,7 @@
>  #include "kvm_cache_regs.h"
>  #include "kvm_emulate.h"
>  #include "smm.h"
> +#include "cpuid.h"
>  #include "trace.h"
>  
>  void kvm_smm_changed(struct kvm_vcpu *vcpu, bool entering_smm)
> @@ -35,3 +36,237 @@ void process_smi(struct kvm_vcpu *vcpu)
>  	vcpu->arch.smi_pending = true;
>  	kvm_make_request(KVM_REQ_EVENT, vcpu);
>  }
> +
> +static u32 enter_smm_get_segment_flags(struct kvm_segment *seg)
> +{
> +	u32 flags = 0;
> +	flags |= seg->g       << 23;
> +	flags |= seg->db      << 22;
> +	flags |= seg->l       << 21;
> +	flags |= seg->avl     << 20;
> +	flags |= seg->present << 15;
> +	flags |= seg->dpl     << 13;
> +	flags |= seg->s       << 12;
> +	flags |= seg->type    << 8;
> +	return flags;
> +}
> +
> +static void enter_smm_save_seg_32(struct kvm_vcpu *vcpu, char *buf, int n)
> +{
> +	struct kvm_segment seg;
> +	int offset;
> +
> +	kvm_get_segment(vcpu, &seg, n);
> +	PUT_SMSTATE(u32, buf, 0x7fa8 + n * 4, seg.selector);
> +
> +	if (n < 3)
> +		offset = 0x7f84 + n * 12;
> +	else
> +		offset = 0x7f2c + (n - 3) * 12;
> +
> +	PUT_SMSTATE(u32, buf, offset + 8, seg.base);
> +	PUT_SMSTATE(u32, buf, offset + 4, seg.limit);
> +	PUT_SMSTATE(u32, buf, offset, enter_smm_get_segment_flags(&seg));
> +}
> +
> +#ifdef CONFIG_X86_64
> +static void enter_smm_save_seg_64(struct kvm_vcpu *vcpu, char *buf, int n)
> +{
> +	struct kvm_segment seg;
> +	int offset;
> +	u16 flags;
> +
> +	kvm_get_segment(vcpu, &seg, n);
> +	offset = 0x7e00 + n * 16;
> +
> +	flags = enter_smm_get_segment_flags(&seg) >> 8;
> +	PUT_SMSTATE(u16, buf, offset, seg.selector);
> +	PUT_SMSTATE(u16, buf, offset + 2, flags);
> +	PUT_SMSTATE(u32, buf, offset + 4, seg.limit);
> +	PUT_SMSTATE(u64, buf, offset + 8, seg.base);
> +}
> +#endif
> +
> +static void enter_smm_save_state_32(struct kvm_vcpu *vcpu, char *buf)
> +{
> +	struct desc_ptr dt;
> +	struct kvm_segment seg;
> +	unsigned long val;
> +	int i;
> +
> +	PUT_SMSTATE(u32, buf, 0x7ffc, kvm_read_cr0(vcpu));
> +	PUT_SMSTATE(u32, buf, 0x7ff8, kvm_read_cr3(vcpu));
> +	PUT_SMSTATE(u32, buf, 0x7ff4, kvm_get_rflags(vcpu));
> +	PUT_SMSTATE(u32, buf, 0x7ff0, kvm_rip_read(vcpu));
> +
> +	for (i = 0; i < 8; i++)
> +		PUT_SMSTATE(u32, buf, 0x7fd0 + i * 4, kvm_register_read_raw(vcpu, i));
> +
> +	kvm_get_dr(vcpu, 6, &val);
> +	PUT_SMSTATE(u32, buf, 0x7fcc, (u32)val);
> +	kvm_get_dr(vcpu, 7, &val);
> +	PUT_SMSTATE(u32, buf, 0x7fc8, (u32)val);
> +
> +	kvm_get_segment(vcpu, &seg, VCPU_SREG_TR);
> +	PUT_SMSTATE(u32, buf, 0x7fc4, seg.selector);
> +	PUT_SMSTATE(u32, buf, 0x7f64, seg.base);
> +	PUT_SMSTATE(u32, buf, 0x7f60, seg.limit);
> +	PUT_SMSTATE(u32, buf, 0x7f5c, enter_smm_get_segment_flags(&seg));
> +
> +	kvm_get_segment(vcpu, &seg, VCPU_SREG_LDTR);
> +	PUT_SMSTATE(u32, buf, 0x7fc0, seg.selector);
> +	PUT_SMSTATE(u32, buf, 0x7f80, seg.base);
> +	PUT_SMSTATE(u32, buf, 0x7f7c, seg.limit);
> +	PUT_SMSTATE(u32, buf, 0x7f78, enter_smm_get_segment_flags(&seg));
> +
> +	static_call(kvm_x86_get_gdt)(vcpu, &dt);
> +	PUT_SMSTATE(u32, buf, 0x7f74, dt.address);
> +	PUT_SMSTATE(u32, buf, 0x7f70, dt.size);
> +
> +	static_call(kvm_x86_get_idt)(vcpu, &dt);
> +	PUT_SMSTATE(u32, buf, 0x7f58, dt.address);
> +	PUT_SMSTATE(u32, buf, 0x7f54, dt.size);
> +
> +	for (i = 0; i < 6; i++)
> +		enter_smm_save_seg_32(vcpu, buf, i);
> +
> +	PUT_SMSTATE(u32, buf, 0x7f14, kvm_read_cr4(vcpu));
> +
> +	/* revision id */
> +	PUT_SMSTATE(u32, buf, 0x7efc, 0x00020000);
> +	PUT_SMSTATE(u32, buf, 0x7ef8, vcpu->arch.smbase);
> +}
> +
> +#ifdef CONFIG_X86_64
> +static void enter_smm_save_state_64(struct kvm_vcpu *vcpu, char *buf)
> +{
> +	struct desc_ptr dt;
> +	struct kvm_segment seg;
> +	unsigned long val;
> +	int i;
> +
> +	for (i = 0; i < 16; i++)
> +		PUT_SMSTATE(u64, buf, 0x7ff8 - i * 8, kvm_register_read_raw(vcpu, i));
> +
> +	PUT_SMSTATE(u64, buf, 0x7f78, kvm_rip_read(vcpu));
> +	PUT_SMSTATE(u32, buf, 0x7f70, kvm_get_rflags(vcpu));
> +
> +	kvm_get_dr(vcpu, 6, &val);
> +	PUT_SMSTATE(u64, buf, 0x7f68, val);
> +	kvm_get_dr(vcpu, 7, &val);
> +	PUT_SMSTATE(u64, buf, 0x7f60, val);
> +
> +	PUT_SMSTATE(u64, buf, 0x7f58, kvm_read_cr0(vcpu));
> +	PUT_SMSTATE(u64, buf, 0x7f50, kvm_read_cr3(vcpu));
> +	PUT_SMSTATE(u64, buf, 0x7f48, kvm_read_cr4(vcpu));
> +
> +	PUT_SMSTATE(u32, buf, 0x7f00, vcpu->arch.smbase);
> +
> +	/* revision id */
> +	PUT_SMSTATE(u32, buf, 0x7efc, 0x00020064);
> +
> +	PUT_SMSTATE(u64, buf, 0x7ed0, vcpu->arch.efer);
> +
> +	kvm_get_segment(vcpu, &seg, VCPU_SREG_TR);
> +	PUT_SMSTATE(u16, buf, 0x7e90, seg.selector);
> +	PUT_SMSTATE(u16, buf, 0x7e92, enter_smm_get_segment_flags(&seg) >> 8);
> +	PUT_SMSTATE(u32, buf, 0x7e94, seg.limit);
> +	PUT_SMSTATE(u64, buf, 0x7e98, seg.base);
> +
> +	static_call(kvm_x86_get_idt)(vcpu, &dt);
> +	PUT_SMSTATE(u32, buf, 0x7e84, dt.size);
> +	PUT_SMSTATE(u64, buf, 0x7e88, dt.address);
> +
> +	kvm_get_segment(vcpu, &seg, VCPU_SREG_LDTR);
> +	PUT_SMSTATE(u16, buf, 0x7e70, seg.selector);
> +	PUT_SMSTATE(u16, buf, 0x7e72, enter_smm_get_segment_flags(&seg) >> 8);
> +	PUT_SMSTATE(u32, buf, 0x7e74, seg.limit);
> +	PUT_SMSTATE(u64, buf, 0x7e78, seg.base);
> +
> +	static_call(kvm_x86_get_gdt)(vcpu, &dt);
> +	PUT_SMSTATE(u32, buf, 0x7e64, dt.size);
> +	PUT_SMSTATE(u64, buf, 0x7e68, dt.address);
> +
> +	for (i = 0; i < 6; i++)
> +		enter_smm_save_seg_64(vcpu, buf, i);
> +}
> +#endif
> +
> +void enter_smm(struct kvm_vcpu *vcpu)
> +{
> +	struct kvm_segment cs, ds;
> +	struct desc_ptr dt;
> +	unsigned long cr0;
> +	char buf[512];
> +
> +	memset(buf, 0, 512);
> +#ifdef CONFIG_X86_64
> +	if (guest_cpuid_has(vcpu, X86_FEATURE_LM))
> +		enter_smm_save_state_64(vcpu, buf);
> +	else
> +#endif
> +		enter_smm_save_state_32(vcpu, buf);
> +
> +	/*
> +	 * Give enter_smm() a chance to make ISA-specific changes to the vCPU
> +	 * state (e.g. leave guest mode) after we've saved the state into the
> +	 * SMM state-save area.
> +	 */
> +	static_call(kvm_x86_enter_smm)(vcpu, buf);
> +
> +	kvm_smm_changed(vcpu, true);
> +	kvm_vcpu_write_guest(vcpu, vcpu->arch.smbase + 0xfe00, buf, sizeof(buf));
> +
> +	if (static_call(kvm_x86_get_nmi_mask)(vcpu))
> +		vcpu->arch.hflags |= HF_SMM_INSIDE_NMI_MASK;
> +	else
> +		static_call(kvm_x86_set_nmi_mask)(vcpu, true);
> +
> +	kvm_set_rflags(vcpu, X86_EFLAGS_FIXED);
> +	kvm_rip_write(vcpu, 0x8000);
> +
> +	cr0 = vcpu->arch.cr0 & ~(X86_CR0_PE | X86_CR0_EM | X86_CR0_TS | X86_CR0_PG);
> +	static_call(kvm_x86_set_cr0)(vcpu, cr0);
> +	vcpu->arch.cr0 = cr0;
> +
> +	static_call(kvm_x86_set_cr4)(vcpu, 0);
> +
> +	/* Undocumented: IDT limit is set to zero on entry to SMM.  */
> +	dt.address = dt.size = 0;
> +	static_call(kvm_x86_set_idt)(vcpu, &dt);
> +
> +	kvm_set_dr(vcpu, 7, DR7_FIXED_1);
> +
> +	cs.selector = (vcpu->arch.smbase >> 4) & 0xffff;
> +	cs.base = vcpu->arch.smbase;
> +
> +	ds.selector = 0;
> +	ds.base = 0;
> +
> +	cs.limit    = ds.limit = 0xffffffff;
> +	cs.type     = ds.type = 0x3;
> +	cs.dpl      = ds.dpl = 0;
> +	cs.db       = ds.db = 0;
> +	cs.s        = ds.s = 1;
> +	cs.l        = ds.l = 0;
> +	cs.g        = ds.g = 1;
> +	cs.avl      = ds.avl = 0;
> +	cs.present  = ds.present = 1;
> +	cs.unusable = ds.unusable = 0;
> +	cs.padding  = ds.padding = 0;
> +
> +	kvm_set_segment(vcpu, &cs, VCPU_SREG_CS);
> +	kvm_set_segment(vcpu, &ds, VCPU_SREG_DS);
> +	kvm_set_segment(vcpu, &ds, VCPU_SREG_ES);
> +	kvm_set_segment(vcpu, &ds, VCPU_SREG_FS);
> +	kvm_set_segment(vcpu, &ds, VCPU_SREG_GS);
> +	kvm_set_segment(vcpu, &ds, VCPU_SREG_SS);
> +
> +#ifdef CONFIG_X86_64
> +	if (guest_cpuid_has(vcpu, X86_FEATURE_LM))
> +		static_call(kvm_x86_set_efer)(vcpu, 0);
> +#endif
> +
> +	kvm_update_cpuid_runtime(vcpu);
> +	kvm_mmu_reset_context(vcpu);
> +}
> diff --git a/arch/x86/kvm/smm.h b/arch/x86/kvm/smm.h
> index d85d4ccd32dd..aacc6dac2c99 100644
> --- a/arch/x86/kvm/smm.h
> +++ b/arch/x86/kvm/smm.h
> @@ -20,6 +20,7 @@ static inline bool is_smm(struct kvm_vcpu *vcpu)
>  }
>  
>  void kvm_smm_changed(struct kvm_vcpu *vcpu, bool in_smm);
> +void enter_smm(struct kvm_vcpu *vcpu);
>  void process_smi(struct kvm_vcpu *vcpu);
>  
>  #endif
> diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
> index e0e461958c81..476b4a6e81ab 100644
> --- a/arch/x86/kvm/x86.c
> +++ b/arch/x86/kvm/x86.c
> @@ -120,7 +120,6 @@ static u64 __read_mostly cr4_reserved_bits = CR4_RESERVED_BITS;
>  
>  static void update_cr8_intercept(struct kvm_vcpu *vcpu);
>  static void process_nmi(struct kvm_vcpu *vcpu);
> -static void enter_smm(struct kvm_vcpu *vcpu);
>  static void __kvm_set_rflags(struct kvm_vcpu *vcpu, unsigned long rflags);
>  static void store_regs(struct kvm_vcpu *vcpu);
>  static int sync_regs(struct kvm_vcpu *vcpu);
> @@ -7043,8 +7042,8 @@ static int vcpu_mmio_read(struct kvm_vcpu *vcpu, gpa_t addr, int len, void *v)
>  	return handled;
>  }
>  
> -static void kvm_set_segment(struct kvm_vcpu *vcpu,
> -			struct kvm_segment *var, int seg)
> +void kvm_set_segment(struct kvm_vcpu *vcpu,
> +		     struct kvm_segment *var, int seg)
>  {
>  	static_call(kvm_x86_set_segment)(vcpu, var, seg);
>  }
> @@ -9968,240 +9967,6 @@ static void process_nmi(struct kvm_vcpu *vcpu)
>  	kvm_make_request(KVM_REQ_EVENT, vcpu);
>  }
>  
> -static u32 enter_smm_get_segment_flags(struct kvm_segment *seg)
> -{
> -	u32 flags = 0;
> -	flags |= seg->g       << 23;
> -	flags |= seg->db      << 22;
> -	flags |= seg->l       << 21;
> -	flags |= seg->avl     << 20;
> -	flags |= seg->present << 15;
> -	flags |= seg->dpl     << 13;
> -	flags |= seg->s       << 12;
> -	flags |= seg->type    << 8;
> -	return flags;
> -}
> -
> -static void enter_smm_save_seg_32(struct kvm_vcpu *vcpu, char *buf, int n)
> -{
> -	struct kvm_segment seg;
> -	int offset;
> -
> -	kvm_get_segment(vcpu, &seg, n);
> -	PUT_SMSTATE(u32, buf, 0x7fa8 + n * 4, seg.selector);
> -
> -	if (n < 3)
> -		offset = 0x7f84 + n * 12;
> -	else
> -		offset = 0x7f2c + (n - 3) * 12;
> -
> -	PUT_SMSTATE(u32, buf, offset + 8, seg.base);
> -	PUT_SMSTATE(u32, buf, offset + 4, seg.limit);
> -	PUT_SMSTATE(u32, buf, offset, enter_smm_get_segment_flags(&seg));
> -}
> -
> -#ifdef CONFIG_X86_64
> -static void enter_smm_save_seg_64(struct kvm_vcpu *vcpu, char *buf, int n)
> -{
> -	struct kvm_segment seg;
> -	int offset;
> -	u16 flags;
> -
> -	kvm_get_segment(vcpu, &seg, n);
> -	offset = 0x7e00 + n * 16;
> -
> -	flags = enter_smm_get_segment_flags(&seg) >> 8;
> -	PUT_SMSTATE(u16, buf, offset, seg.selector);
> -	PUT_SMSTATE(u16, buf, offset + 2, flags);
> -	PUT_SMSTATE(u32, buf, offset + 4, seg.limit);
> -	PUT_SMSTATE(u64, buf, offset + 8, seg.base);
> -}
> -#endif
> -
> -static void enter_smm_save_state_32(struct kvm_vcpu *vcpu, char *buf)
> -{
> -	struct desc_ptr dt;
> -	struct kvm_segment seg;
> -	unsigned long val;
> -	int i;
> -
> -	PUT_SMSTATE(u32, buf, 0x7ffc, kvm_read_cr0(vcpu));
> -	PUT_SMSTATE(u32, buf, 0x7ff8, kvm_read_cr3(vcpu));
> -	PUT_SMSTATE(u32, buf, 0x7ff4, kvm_get_rflags(vcpu));
> -	PUT_SMSTATE(u32, buf, 0x7ff0, kvm_rip_read(vcpu));
> -
> -	for (i = 0; i < 8; i++)
> -		PUT_SMSTATE(u32, buf, 0x7fd0 + i * 4, kvm_register_read_raw(vcpu, i));
> -
> -	kvm_get_dr(vcpu, 6, &val);
> -	PUT_SMSTATE(u32, buf, 0x7fcc, (u32)val);
> -	kvm_get_dr(vcpu, 7, &val);
> -	PUT_SMSTATE(u32, buf, 0x7fc8, (u32)val);
> -
> -	kvm_get_segment(vcpu, &seg, VCPU_SREG_TR);
> -	PUT_SMSTATE(u32, buf, 0x7fc4, seg.selector);
> -	PUT_SMSTATE(u32, buf, 0x7f64, seg.base);
> -	PUT_SMSTATE(u32, buf, 0x7f60, seg.limit);
> -	PUT_SMSTATE(u32, buf, 0x7f5c, enter_smm_get_segment_flags(&seg));
> -
> -	kvm_get_segment(vcpu, &seg, VCPU_SREG_LDTR);
> -	PUT_SMSTATE(u32, buf, 0x7fc0, seg.selector);
> -	PUT_SMSTATE(u32, buf, 0x7f80, seg.base);
> -	PUT_SMSTATE(u32, buf, 0x7f7c, seg.limit);
> -	PUT_SMSTATE(u32, buf, 0x7f78, enter_smm_get_segment_flags(&seg));
> -
> -	static_call(kvm_x86_get_gdt)(vcpu, &dt);
> -	PUT_SMSTATE(u32, buf, 0x7f74, dt.address);
> -	PUT_SMSTATE(u32, buf, 0x7f70, dt.size);
> -
> -	static_call(kvm_x86_get_idt)(vcpu, &dt);
> -	PUT_SMSTATE(u32, buf, 0x7f58, dt.address);
> -	PUT_SMSTATE(u32, buf, 0x7f54, dt.size);
> -
> -	for (i = 0; i < 6; i++)
> -		enter_smm_save_seg_32(vcpu, buf, i);
> -
> -	PUT_SMSTATE(u32, buf, 0x7f14, kvm_read_cr4(vcpu));
> -
> -	/* revision id */
> -	PUT_SMSTATE(u32, buf, 0x7efc, 0x00020000);
> -	PUT_SMSTATE(u32, buf, 0x7ef8, vcpu->arch.smbase);
> -}
> -
> -#ifdef CONFIG_X86_64
> -static void enter_smm_save_state_64(struct kvm_vcpu *vcpu, char *buf)
> -{
> -	struct desc_ptr dt;
> -	struct kvm_segment seg;
> -	unsigned long val;
> -	int i;
> -
> -	for (i = 0; i < 16; i++)
> -		PUT_SMSTATE(u64, buf, 0x7ff8 - i * 8, kvm_register_read_raw(vcpu, i));
> -
> -	PUT_SMSTATE(u64, buf, 0x7f78, kvm_rip_read(vcpu));
> -	PUT_SMSTATE(u32, buf, 0x7f70, kvm_get_rflags(vcpu));
> -
> -	kvm_get_dr(vcpu, 6, &val);
> -	PUT_SMSTATE(u64, buf, 0x7f68, val);
> -	kvm_get_dr(vcpu, 7, &val);
> -	PUT_SMSTATE(u64, buf, 0x7f60, val);
> -
> -	PUT_SMSTATE(u64, buf, 0x7f58, kvm_read_cr0(vcpu));
> -	PUT_SMSTATE(u64, buf, 0x7f50, kvm_read_cr3(vcpu));
> -	PUT_SMSTATE(u64, buf, 0x7f48, kvm_read_cr4(vcpu));
> -
> -	PUT_SMSTATE(u32, buf, 0x7f00, vcpu->arch.smbase);
> -
> -	/* revision id */
> -	PUT_SMSTATE(u32, buf, 0x7efc, 0x00020064);
> -
> -	PUT_SMSTATE(u64, buf, 0x7ed0, vcpu->arch.efer);
> -
> -	kvm_get_segment(vcpu, &seg, VCPU_SREG_TR);
> -	PUT_SMSTATE(u16, buf, 0x7e90, seg.selector);
> -	PUT_SMSTATE(u16, buf, 0x7e92, enter_smm_get_segment_flags(&seg) >> 8);
> -	PUT_SMSTATE(u32, buf, 0x7e94, seg.limit);
> -	PUT_SMSTATE(u64, buf, 0x7e98, seg.base);
> -
> -	static_call(kvm_x86_get_idt)(vcpu, &dt);
> -	PUT_SMSTATE(u32, buf, 0x7e84, dt.size);
> -	PUT_SMSTATE(u64, buf, 0x7e88, dt.address);
> -
> -	kvm_get_segment(vcpu, &seg, VCPU_SREG_LDTR);
> -	PUT_SMSTATE(u16, buf, 0x7e70, seg.selector);
> -	PUT_SMSTATE(u16, buf, 0x7e72, enter_smm_get_segment_flags(&seg) >> 8);
> -	PUT_SMSTATE(u32, buf, 0x7e74, seg.limit);
> -	PUT_SMSTATE(u64, buf, 0x7e78, seg.base);
> -
> -	static_call(kvm_x86_get_gdt)(vcpu, &dt);
> -	PUT_SMSTATE(u32, buf, 0x7e64, dt.size);
> -	PUT_SMSTATE(u64, buf, 0x7e68, dt.address);
> -
> -	for (i = 0; i < 6; i++)
> -		enter_smm_save_seg_64(vcpu, buf, i);
> -}
> -#endif
> -
> -static void enter_smm(struct kvm_vcpu *vcpu)
> -{
> -	struct kvm_segment cs, ds;
> -	struct desc_ptr dt;
> -	unsigned long cr0;
> -	char buf[512];
> -
> -	memset(buf, 0, 512);
> -#ifdef CONFIG_X86_64
> -	if (guest_cpuid_has(vcpu, X86_FEATURE_LM))
> -		enter_smm_save_state_64(vcpu, buf);
> -	else
> -#endif
> -		enter_smm_save_state_32(vcpu, buf);
> -
> -	/*
> -	 * Give enter_smm() a chance to make ISA-specific changes to the vCPU
> -	 * state (e.g. leave guest mode) after we've saved the state into the
> -	 * SMM state-save area.
> -	 */
> -	static_call(kvm_x86_enter_smm)(vcpu, buf);
> -
> -	kvm_smm_changed(vcpu, true);
> -	kvm_vcpu_write_guest(vcpu, vcpu->arch.smbase + 0xfe00, buf, sizeof(buf));
> -
> -	if (static_call(kvm_x86_get_nmi_mask)(vcpu))
> -		vcpu->arch.hflags |= HF_SMM_INSIDE_NMI_MASK;
> -	else
> -		static_call(kvm_x86_set_nmi_mask)(vcpu, true);
> -
> -	kvm_set_rflags(vcpu, X86_EFLAGS_FIXED);
> -	kvm_rip_write(vcpu, 0x8000);
> -
> -	cr0 = vcpu->arch.cr0 & ~(X86_CR0_PE | X86_CR0_EM | X86_CR0_TS | X86_CR0_PG);
> -	static_call(kvm_x86_set_cr0)(vcpu, cr0);
> -	vcpu->arch.cr0 = cr0;
> -
> -	static_call(kvm_x86_set_cr4)(vcpu, 0);
> -
> -	/* Undocumented: IDT limit is set to zero on entry to SMM.  */
> -	dt.address = dt.size = 0;
> -	static_call(kvm_x86_set_idt)(vcpu, &dt);
> -
> -	kvm_set_dr(vcpu, 7, DR7_FIXED_1);
> -
> -	cs.selector = (vcpu->arch.smbase >> 4) & 0xffff;
> -	cs.base = vcpu->arch.smbase;
> -
> -	ds.selector = 0;
> -	ds.base = 0;
> -
> -	cs.limit    = ds.limit = 0xffffffff;
> -	cs.type     = ds.type = 0x3;
> -	cs.dpl      = ds.dpl = 0;
> -	cs.db       = ds.db = 0;
> -	cs.s        = ds.s = 1;
> -	cs.l        = ds.l = 0;
> -	cs.g        = ds.g = 1;
> -	cs.avl      = ds.avl = 0;
> -	cs.present  = ds.present = 1;
> -	cs.unusable = ds.unusable = 0;
> -	cs.padding  = ds.padding = 0;
> -
> -	kvm_set_segment(vcpu, &cs, VCPU_SREG_CS);
> -	kvm_set_segment(vcpu, &ds, VCPU_SREG_DS);
> -	kvm_set_segment(vcpu, &ds, VCPU_SREG_ES);
> -	kvm_set_segment(vcpu, &ds, VCPU_SREG_FS);
> -	kvm_set_segment(vcpu, &ds, VCPU_SREG_GS);
> -	kvm_set_segment(vcpu, &ds, VCPU_SREG_SS);
> -
> -#ifdef CONFIG_X86_64
> -	if (guest_cpuid_has(vcpu, X86_FEATURE_LM))
> -		static_call(kvm_x86_set_efer)(vcpu, 0);
> -#endif
> -
> -	kvm_update_cpuid_runtime(vcpu);
> -	kvm_mmu_reset_context(vcpu);
> -}
> -
>  void kvm_make_scan_ioapic_request_mask(struct kvm *kvm,
>  				       unsigned long *vcpu_bitmap)
>  {


Looks OK to me, but I might have missed something.

Reviewed-by: Maxim Levitsky <mlevitsk@redhat.com>

Best regards,
	Maxim Levitsky