KVM: x86: move SMM entry to a new file

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>
Reviewed-by: Maxim Levitsky <mlevitsk@redhat.com>
Message-Id: <20220929172016.319443-3-pbonzini@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

1 files changed, 235 insertions, 0 deletions

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);
+}