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From:   Maxim Levitsky <mlevitsk@redhat.com>
To:     kvm@vger.kernel.org
Cc:     Sean Christopherson <seanjc@google.com>, x86@kernel.org,
        Kees Cook <keescook@chromium.org>,
        Dave Hansen <dave.hansen@linux.intel.com>,
        linux-kernel@vger.kernel.org, "H. Peter Anvin" <hpa@zytor.com>,
        Borislav Petkov <bp@alien8.de>, Joerg Roedel <joro@8bytes.org>,
        Ingo Molnar <mingo@redhat.com>,
        Paolo Bonzini <pbonzini@redhat.com>,
        Thomas Gleixner <tglx@linutronix.de>,
        Vitaly Kuznetsov <vkuznets@redhat.com>,
        Wanpeng Li <wanpengli@tencent.com>,
        Jim Mattson <jmattson@google.com>,
        Maxim Levitsky <mlevitsk@redhat.com>
Subject: [PATCH v2 08/11] KVM: x86: emulator/smm: use smram struct for 32 bit smram load/restore
Date:   Tue, 21 Jun 2022 18:08:59 +0300
Message-Id: <20220621150902.46126-9-mlevitsk@redhat.com>
In-Reply-To: <20220621150902.46126-1-mlevitsk@redhat.com>
References: <20220621150902.46126-1-mlevitsk@redhat.com>
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Use kvm_smram_state_32 struct to save/restore 32 bit SMM state
(used when X86_FEATURE_LM is not present in the guest CPUID).

Signed-off-by: Maxim Levitsky <mlevitsk@redhat.com>
---
 arch/x86/kvm/emulate.c | 81 +++++++++++++++---------------------------
 arch/x86/kvm/x86.c     | 75 +++++++++++++++++---------------------
 2 files changed, 60 insertions(+), 96 deletions(-)

diff --git a/arch/x86/kvm/emulate.c b/arch/x86/kvm/emulate.c
index ce186aebca8e83..6d263906054689 100644
--- a/arch/x86/kvm/emulate.c
+++ b/arch/x86/kvm/emulate.c
@@ -2367,25 +2367,17 @@ static void rsm_set_desc_flags(struct desc_struct *desc, u32 flags)
 	desc->type = (flags >>  8) & 15;
 }
 
-static int rsm_load_seg_32(struct x86_emulate_ctxt *ctxt, const char *smstate,
+static void rsm_load_seg_32(struct x86_emulate_ctxt *ctxt,
+			   struct kvm_smm_seg_state_32 *state,
+			   u16 selector,
 			   int n)
 {
 	struct desc_struct desc;
-	int offset;
-	u16 selector;
-
-	selector = GET_SMSTATE(u32, smstate, 0x7fa8 + n * 4);
-
-	if (n < 3)
-		offset = 0x7f84 + n * 12;
-	else
-		offset = 0x7f2c + (n - 3) * 12;
 
-	set_desc_base(&desc,      GET_SMSTATE(u32, smstate, offset + 8));
-	set_desc_limit(&desc,     GET_SMSTATE(u32, smstate, offset + 4));
-	rsm_set_desc_flags(&desc, GET_SMSTATE(u32, smstate, offset));
+	set_desc_base(&desc,      state->base);
+	set_desc_limit(&desc,     state->limit);
+	rsm_set_desc_flags(&desc, state->flags);
 	ctxt->ops->set_segment(ctxt, selector, &desc, 0, n);
-	return X86EMUL_CONTINUE;
 }
 
 #ifdef CONFIG_X86_64
@@ -2456,63 +2448,46 @@ static int rsm_enter_protected_mode(struct x86_emulate_ctxt *ctxt,
 }
 
 static int rsm_load_state_32(struct x86_emulate_ctxt *ctxt,
-			     const char *smstate)
+			     struct kvm_smram_state_32 *smstate)
 {
-	struct desc_struct desc;
 	struct desc_ptr dt;
-	u16 selector;
-	u32 val, cr0, cr3, cr4;
 	int i;
 
-	cr0 =                      GET_SMSTATE(u32, smstate, 0x7ffc);
-	cr3 =                      GET_SMSTATE(u32, smstate, 0x7ff8);
-	ctxt->eflags =             GET_SMSTATE(u32, smstate, 0x7ff4) | X86_EFLAGS_FIXED;
-	ctxt->_eip =               GET_SMSTATE(u32, smstate, 0x7ff0);
+	ctxt->eflags =  smstate->eflags | X86_EFLAGS_FIXED;
+	ctxt->_eip =  smstate->eip;
 
 	for (i = 0; i < 8; i++)
-		*reg_write(ctxt, i) = GET_SMSTATE(u32, smstate, 0x7fd0 + i * 4);
-
-	val = GET_SMSTATE(u32, smstate, 0x7fcc);
+		*reg_write(ctxt, i) = smstate->gprs[i];
 
-	if (ctxt->ops->set_dr(ctxt, 6, val))
+	if (ctxt->ops->set_dr(ctxt, 6, smstate->dr6))
 		return X86EMUL_UNHANDLEABLE;
-
-	val = GET_SMSTATE(u32, smstate, 0x7fc8);
-
-	if (ctxt->ops->set_dr(ctxt, 7, val))
+	if (ctxt->ops->set_dr(ctxt, 7, smstate->dr7))
 		return X86EMUL_UNHANDLEABLE;
 
-	selector =                 GET_SMSTATE(u32, smstate, 0x7fc4);
-	set_desc_base(&desc,       GET_SMSTATE(u32, smstate, 0x7f64));
-	set_desc_limit(&desc,      GET_SMSTATE(u32, smstate, 0x7f60));
-	rsm_set_desc_flags(&desc,  GET_SMSTATE(u32, smstate, 0x7f5c));
-	ctxt->ops->set_segment(ctxt, selector, &desc, 0, VCPU_SREG_TR);
+	rsm_load_seg_32(ctxt, &smstate->tr, smstate->tr_sel, VCPU_SREG_TR);
+	rsm_load_seg_32(ctxt, &smstate->ldtr, smstate->ldtr_sel, VCPU_SREG_LDTR);
 
-	selector =                 GET_SMSTATE(u32, smstate, 0x7fc0);
-	set_desc_base(&desc,       GET_SMSTATE(u32, smstate, 0x7f80));
-	set_desc_limit(&desc,      GET_SMSTATE(u32, smstate, 0x7f7c));
-	rsm_set_desc_flags(&desc,  GET_SMSTATE(u32, smstate, 0x7f78));
-	ctxt->ops->set_segment(ctxt, selector, &desc, 0, VCPU_SREG_LDTR);
 
-	dt.address =               GET_SMSTATE(u32, smstate, 0x7f74);
-	dt.size =                  GET_SMSTATE(u32, smstate, 0x7f70);
+	dt.address =               smstate->gdtr.base;
+	dt.size =                  smstate->gdtr.limit;
 	ctxt->ops->set_gdt(ctxt, &dt);
 
-	dt.address =               GET_SMSTATE(u32, smstate, 0x7f58);
-	dt.size =                  GET_SMSTATE(u32, smstate, 0x7f54);
+	dt.address =               smstate->idtr.base;
+	dt.size =                  smstate->idtr.limit;
 	ctxt->ops->set_idt(ctxt, &dt);
 
-	for (i = 0; i < 6; i++) {
-		int r = rsm_load_seg_32(ctxt, smstate, i);
-		if (r != X86EMUL_CONTINUE)
-			return r;
-	}
+	rsm_load_seg_32(ctxt, &smstate->es, smstate->es_sel, VCPU_SREG_ES);
+	rsm_load_seg_32(ctxt, &smstate->cs, smstate->cs_sel, VCPU_SREG_CS);
+	rsm_load_seg_32(ctxt, &smstate->ss, smstate->ss_sel, VCPU_SREG_SS);
 
-	cr4 = GET_SMSTATE(u32, smstate, 0x7f14);
+	rsm_load_seg_32(ctxt, &smstate->ds, smstate->ds_sel, VCPU_SREG_DS);
+	rsm_load_seg_32(ctxt, &smstate->fs, smstate->fs_sel, VCPU_SREG_FS);
+	rsm_load_seg_32(ctxt, &smstate->gs, smstate->gs_sel, VCPU_SREG_GS);
 
-	ctxt->ops->set_smbase(ctxt, GET_SMSTATE(u32, smstate, 0x7ef8));
+	ctxt->ops->set_smbase(ctxt, smstate->smbase);
 
-	return rsm_enter_protected_mode(ctxt, cr0, cr3, cr4);
+	return rsm_enter_protected_mode(ctxt, smstate->cr0,
+					smstate->cr3, smstate->cr4);
 }
 
 #ifdef CONFIG_X86_64
@@ -2657,7 +2632,7 @@ static int em_rsm(struct x86_emulate_ctxt *ctxt)
 		ret = rsm_load_state_64(ctxt, buf);
 	else
 #endif
-		ret = rsm_load_state_32(ctxt, buf);
+		ret = rsm_load_state_32(ctxt, (struct kvm_smram_state_32 *)buf);
 
 	if (ret != X86EMUL_CONTINUE)
 		goto emulate_shutdown;
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 00e23dc518e091..a1bbf2ed520769 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -9674,22 +9674,18 @@ static u32 enter_smm_get_segment_flags(struct kvm_segment *seg)
 	return flags;
 }
 
-static void enter_smm_save_seg_32(struct kvm_vcpu *vcpu, char *buf, int n)
+static void enter_smm_save_seg_32(struct kvm_vcpu *vcpu,
+					 struct kvm_smm_seg_state_32 *state,
+					 u32 *selector,
+					 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));
+	*selector = seg.selector;
+	state->base = seg.base;
+	state->limit = seg.limit;
+	state->flags = enter_smm_get_segment_flags(&seg);
 }
 
 #ifdef CONFIG_X86_64
@@ -9710,54 +9706,47 @@ static void enter_smm_save_seg_64(struct kvm_vcpu *vcpu, char *buf, int n)
 }
 #endif
 
-static void enter_smm_save_state_32(struct kvm_vcpu *vcpu, char *buf)
+static void enter_smm_save_state_32(struct kvm_vcpu *vcpu, struct kvm_smram_state_32 *smram)
 {
 	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));
+	smram->cr0     = kvm_read_cr0(vcpu);
+	smram->cr3     = kvm_read_cr3(vcpu);
+	smram->eflags  = kvm_get_rflags(vcpu);
+	smram->eip     = kvm_rip_read(vcpu);
 
 	for (i = 0; i < 8; i++)
-		put_smstate(u32, buf, 0x7fd0 + i * 4, kvm_register_read_raw(vcpu, i));
+		smram->gprs[i] = kvm_register_read_raw(vcpu, i);
 
 	kvm_get_dr(vcpu, 6, &val);
-	put_smstate(u32, buf, 0x7fcc, (u32)val);
+	smram->dr6     = (u32)val;
 	kvm_get_dr(vcpu, 7, &val);
-	put_smstate(u32, buf, 0x7fc8, (u32)val);
+	smram->dr7     = (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));
+	enter_smm_save_seg_32(vcpu, &smram->tr, &smram->tr_sel, VCPU_SREG_TR);
+	enter_smm_save_seg_32(vcpu, &smram->ldtr, &smram->ldtr_sel, VCPU_SREG_LDTR);
 
 	static_call(kvm_x86_get_gdt)(vcpu, &dt);
-	put_smstate(u32, buf, 0x7f74, dt.address);
-	put_smstate(u32, buf, 0x7f70, dt.size);
+	smram->gdtr.base = dt.address;
+	smram->gdtr.limit = dt.size;
 
 	static_call(kvm_x86_get_idt)(vcpu, &dt);
-	put_smstate(u32, buf, 0x7f58, dt.address);
-	put_smstate(u32, buf, 0x7f54, dt.size);
+	smram->idtr.base = dt.address;
+	smram->idtr.limit = dt.size;
 
-	for (i = 0; i < 6; i++)
-		enter_smm_save_seg_32(vcpu, buf, i);
+	enter_smm_save_seg_32(vcpu, &smram->es, &smram->es_sel, VCPU_SREG_ES);
+	enter_smm_save_seg_32(vcpu, &smram->cs, &smram->cs_sel, VCPU_SREG_CS);
+	enter_smm_save_seg_32(vcpu, &smram->ss, &smram->ss_sel, VCPU_SREG_SS);
 
-	put_smstate(u32, buf, 0x7f14, kvm_read_cr4(vcpu));
+	enter_smm_save_seg_32(vcpu, &smram->ds, &smram->ds_sel, VCPU_SREG_DS);
+	enter_smm_save_seg_32(vcpu, &smram->fs, &smram->fs_sel, VCPU_SREG_FS);
+	enter_smm_save_seg_32(vcpu, &smram->gs, &smram->gs_sel, VCPU_SREG_GS);
 
-	/* revision id */
-	put_smstate(u32, buf, 0x7efc, 0x00020000);
-	put_smstate(u32, buf, 0x7ef8, vcpu->arch.smbase);
+	smram->cr4 = kvm_read_cr4(vcpu);
+	smram->smm_revision = 0x00020000;
+	smram->smbase = vcpu->arch.smbase;
 }
 
 #ifdef CONFIG_X86_64
@@ -9828,7 +9817,7 @@ static void enter_smm(struct kvm_vcpu *vcpu)
 		enter_smm_save_state_64(vcpu, buf);
 	else
 #endif
-		enter_smm_save_state_32(vcpu, buf);
+		enter_smm_save_state_32(vcpu, (struct kvm_smram_state_32 *)buf);
 
 	/*
 	 * Give enter_smm() a chance to make ISA-specific changes to the vCPU
-- 
2.26.3