linux-kernel - [PATCH 11/11] KVM: x86: add SMM to the MMU role, support SMRAM address space

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Date:	Mon, 18 May 2015 15:48:43 +0200
From:	Paolo Bonzini <pbonzini@...hat.com>
To:	linux-kernel@...r.kernel.org, kvm@...r.kernel.org
Cc:	Xiao Guangrong <guangrong.xiao@...ux.intel.com>,
	rkrcmar@...hat.com, bdas@...hat.com
Subject: [PATCH 11/11] KVM: x86: add SMM to the MMU role, support SMRAM address space

This is now very simple to do.  The only interesting part is a simple
trick to find the right memslot in gfn_to_rmap, retrieving the address
space from the spte role word.

The comment on top of union kvm_mmu_page_role has been stale forever,
so remove it.  Speaking of stale code, remove pad_for_nice_hex_output
too: it was splitting the "access" bitfield across two bytes and thus
had effectively turned into pad_for_ugly_hex_output.

Signed-off-by: Paolo Bonzini <pbonzini@...hat.com>
---
 arch/x86/include/asm/kvm_host.h | 19 ++++++++-----------
 arch/x86/kvm/mmu.c              |  7 ++++++-
 arch/x86/kvm/x86.c              |  1 +
 3 files changed, 15 insertions(+), 12 deletions(-)

diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
index d7957733de61..5dd9d960595c 100644
--- a/arch/x86/include/asm/kvm_host.h
+++ b/arch/x86/include/asm/kvm_host.h
@@ -184,23 +184,12 @@ struct kvm_mmu_memory_cache {
 	void *objects[KVM_NR_MEM_OBJS];
 };
 
-/*
- * kvm_mmu_page_role, below, is defined as:
- *
- *   bits 0:3 - total guest paging levels (2-4, or zero for real mode)
- *   bits 4:7 - page table level for this shadow (1-4)
- *   bits 8:9 - page table quadrant for 2-level guests
- *   bit   16 - direct mapping of virtual to physical mapping at gfn
- *              used for real mode and two-dimensional paging
- *   bits 17:19 - common access permissions for all ptes in this shadow page
- */
 union kvm_mmu_page_role {
 	unsigned word;
 	struct {
 		unsigned level:4;
 		unsigned cr4_pae:1;
 		unsigned quadrant:2;
-		unsigned pad_for_nice_hex_output:6;
 		unsigned direct:1;
 		unsigned access:3;
 		unsigned invalid:1;
@@ -208,6 +198,7 @@ union kvm_mmu_page_role {
 		unsigned cr0_wp:1;
 		unsigned smep_andnot_wp:1;
 		unsigned smap_andnot_wp:1;
+		unsigned smm:1;
 	};
 };
 
@@ -1118,6 +1109,12 @@ enum {
 #define HF_SMM_MASK		(1 << 6)
 #define HF_SMM_INSIDE_NMI_MASK	(1 << 7)
 
+#define __KVM_VCPU_MULTIPLE_ADDRESS_SPACE
+#define KVM_ADDRESS_SPACE_NUM 2
+
+#define kvm_arch_vcpu_memslots_id(vcpu) ((vcpu)->arch.hflags & HF_SMM_MASK ? 1 : 0)
+#define kvm_memslots_for_spte_role(kvm, role) __kvm_memslots(kvm, (role).smm)
+
 /*
  * Hardware virtualization extension instructions may fault if a
  * reboot turns off virtualization while processes are running.
diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c
index b7e94a662f4e..92436bc4f3e0 100644
--- a/arch/x86/kvm/mmu.c
+++ b/arch/x86/kvm/mmu.c
@@ -1041,9 +1041,11 @@ static unsigned long *__gfn_to_rmap(gfn_t gfn, int level,
  */
 static unsigned long *gfn_to_rmap(struct kvm *kvm, gfn_t gfn, struct kvm_mmu_page *sp)
 {
+	struct kvm_memslots *slots;
 	struct kvm_memory_slot *slot;
 
-	slot = gfn_to_memslot(kvm, gfn);
+	slots = kvm_memslots_for_spte_role(kvm, sp->role);
+	slot = __gfn_to_memslot(slots, gfn);
 	return __gfn_to_rmap(gfn, sp->role.level, slot);
 }
 
@@ -3918,6 +3920,7 @@ static void init_kvm_tdp_mmu(struct kvm_vcpu *vcpu)
 	struct kvm_mmu *context = &vcpu->arch.mmu;
 
 	context->base_role.word = 0;
+	context->base_role.smm = is_smm(vcpu);
 	context->page_fault = tdp_page_fault;
 	context->sync_page = nonpaging_sync_page;
 	context->invlpg = nonpaging_invlpg;
@@ -3979,6 +3982,7 @@ void kvm_init_shadow_mmu(struct kvm_vcpu *vcpu)
 		= smep && !is_write_protection(vcpu);
 	context->base_role.smap_andnot_wp
 		= smap && !is_write_protection(vcpu);
+	context->base_role.smm = is_smm(vcpu);
 }
 EXPORT_SYMBOL_GPL(kvm_init_shadow_mmu);
 
@@ -4261,6 +4265,7 @@ void kvm_mmu_pte_write(struct kvm_vcpu *vcpu, gpa_t gpa,
 		.nxe = 1,
 		.smep_andnot_wp = 1,
 		.smap_andnot_wp = 1,
+		.smm = 1,
 	};
 
 	/*
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index bb637e893e13..8a05770b9fa1 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -5473,6 +5473,7 @@ void kvm_set_hflags(struct kvm_vcpu *vcpu, unsigned emul_flags)
 	}
 
 	vcpu->arch.hflags = emul_flags;
+	kvm_mmu_reset_context(vcpu);
 }
 
 static int kvm_vcpu_check_hw_bp(unsigned long addr, u32 type, u32 dr7,
-- 
1.8.3.1
--
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