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Commit c550d539 authored by James Hogan's avatar James Hogan
Browse files

KVM: MIPS: Remove duplicated ASIDs from vcpu 



The kvm_vcpu_arch structure contains both mm_structs for allocating MMU
contexts (primarily the ASID) but it also copies the resulting ASIDs
into guest_{user,kernel}_asid[] arrays which are referenced from uasm
generated code.

This duplication doesn't seem to serve any purpose, and it gets in the
way of generalising the ASID handling across guest kernel/user modes, so
lets just extract the ASID straight out of the mm_struct on demand, and
in fact there are convenient cpu_context() and cpu_asid() macros for
doing so.

To reduce the verbosity of this code we do also add kern_mm and user_mm
local variables where the kernel and user mm_structs are used.

Signed-off-by: default avatarJames Hogan <james.hogan@imgtec.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: "Radim Krčmář" <rkrcmar@redhat.com>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: linux-mips@linux-mips.org
Cc: kvm@vger.kernel.org
parent 1581ff3d

arch/mips/include/asm/kvm_host.h

+1 −3
Original line number Diff line number Diff line
@@ -321,9 +321,7 @@ struct kvm_vcpu_arch { 
	/* S/W Based TLB for guest */

	struct kvm_mips_tlb guest_tlb[KVM_MIPS_GUEST_TLB_SIZE];



	/* Cached guest kernel/user ASIDs */

	u32 guest_user_asid[NR_CPUS];

	u32 guest_kernel_asid[NR_CPUS];

	/* Guest kernel/user [partial] mm */

	struct mm_struct guest_kernel_mm, guest_user_mm;



	/* Guest ASID of last user mode execution */

arch/mips/kvm/emulate.c

+7 −6
Original line number Diff line number Diff line
@@ -856,6 +856,8 @@ enum emulation_result kvm_mips_emul_tlbr(struct kvm_vcpu *vcpu) 
static void kvm_mips_invalidate_guest_tlb(struct kvm_vcpu *vcpu,

					  struct kvm_mips_tlb *tlb)

{

	struct mm_struct *kern_mm = &vcpu->arch.guest_kernel_mm;

	struct mm_struct *user_mm = &vcpu->arch.guest_user_mm;

	int cpu, i;

	bool user;
@@ -879,8 +881,8 @@ static void kvm_mips_invalidate_guest_tlb(struct kvm_vcpu *vcpu, 
		if (i == cpu)

			continue;

		if (user)

			vcpu->arch.guest_user_asid[i] = 0;

		vcpu->arch.guest_kernel_asid[i] = 0;

			cpu_context(i, user_mm) = 0;

		cpu_context(i, kern_mm) = 0;

	}



	preempt_enable();
@@ -1056,6 +1058,7 @@ enum emulation_result kvm_mips_emulate_CP0(union mips_instruction inst, 
					   struct kvm_vcpu *vcpu)

{

	struct mips_coproc *cop0 = vcpu->arch.cop0;

	struct mm_struct *kern_mm = &vcpu->arch.guest_kernel_mm;

	enum emulation_result er = EMULATE_DONE;

	u32 rt, rd, sel;

	unsigned long curr_pc;
@@ -1178,13 +1181,11 @@ enum emulation_result kvm_mips_emulate_CP0(union mips_instruction inst, 
					 */

					preempt_disable();

					cpu = smp_processor_id();

					kvm_get_new_mmu_context(&vcpu->arch.guest_kernel_mm,

					kvm_get_new_mmu_context(kern_mm,

								cpu, vcpu);

					vcpu->arch.guest_kernel_asid[cpu] =

						vcpu->arch.guest_kernel_mm.context.asid[cpu];

					for_each_possible_cpu(i)

						if (i != cpu)

							vcpu->arch.guest_kernel_asid[i] = 0;

							cpu_context(i, kern_mm) = 0;

					preempt_enable();

				}

				kvm_write_c0_guest_entryhi(cop0,

arch/mips/kvm/entry.c

+13 −9
Original line number Diff line number Diff line
@@ -12,6 +12,7 @@ 
 */



#include <linux/kvm_host.h>

#include <linux/log2.h>

#include <asm/msa.h>

#include <asm/setup.h>

#include <asm/uasm.h>
@@ -286,23 +287,26 @@ static void *kvm_mips_build_enter_guest(void *addr) 
	uasm_i_andi(&p, T0, T0, KSU_USER | ST0_ERL | ST0_EXL);

	uasm_i_xori(&p, T0, T0, KSU_USER);

	uasm_il_bnez(&p, &r, T0, label_kernel_asid);

	 UASM_i_ADDIU(&p, T1, K1,

		      offsetof(struct kvm_vcpu_arch, guest_kernel_asid));

	 UASM_i_ADDIU(&p, T1, K1, offsetof(struct kvm_vcpu_arch,

					   guest_kernel_mm.context.asid));

	/* else user */

	UASM_i_ADDIU(&p, T1, K1,

		     offsetof(struct kvm_vcpu_arch, guest_user_asid));

	UASM_i_ADDIU(&p, T1, K1, offsetof(struct kvm_vcpu_arch,

					  guest_user_mm.context.asid));

	uasm_l_kernel_asid(&l, p);



	/* t1: contains the base of the ASID array, need to get the cpu id  */

	/* smp_processor_id */

	uasm_i_lw(&p, T2, offsetof(struct thread_info, cpu), GP);

	/* x4 */

	uasm_i_sll(&p, T2, T2, 2);

	/* index the ASID array */

	uasm_i_sll(&p, T2, T2, ilog2(sizeof(long)));

	UASM_i_ADDU(&p, T3, T1, T2);

	uasm_i_lw(&p, K0, 0, T3);

	UASM_i_LW(&p, K0, 0, T3);

#ifdef CONFIG_MIPS_ASID_BITS_VARIABLE

	/* x sizeof(struct cpuinfo_mips)/4 */

	uasm_i_addiu(&p, T3, ZERO, sizeof(struct cpuinfo_mips)/4);

	/*

	 * reuse ASID array offset

	 * cpuinfo_mips is a multiple of sizeof(long)

	 */

	uasm_i_addiu(&p, T3, ZERO, sizeof(struct cpuinfo_mips)/sizeof(long));

	uasm_i_mul(&p, T2, T2, T3);



	UASM_i_LA_mostly(&p, AT, (long)&cpu_data[0].asid_mask);

arch/mips/kvm/mips.c

+3 −5
Original line number Diff line number Diff line
@@ -413,6 +413,7 @@ int kvm_arch_vcpu_ioctl_set_guest_debug(struct kvm_vcpu *vcpu, 
/* Must be called with preemption disabled, just before entering guest */

static void kvm_mips_check_asids(struct kvm_vcpu *vcpu)

{

	struct mm_struct *user_mm = &vcpu->arch.guest_user_mm;

	struct mips_coproc *cop0 = vcpu->arch.cop0;

	int i, cpu = smp_processor_id();

	unsigned int gasid;
@@ -426,13 +427,10 @@ static void kvm_mips_check_asids(struct kvm_vcpu *vcpu) 
	if (!KVM_GUEST_KERNEL_MODE(vcpu)) {

		gasid = kvm_read_c0_guest_entryhi(cop0) & KVM_ENTRYHI_ASID;

		if (gasid != vcpu->arch.last_user_gasid) {

			kvm_get_new_mmu_context(&vcpu->arch.guest_user_mm, cpu,

						vcpu);

			vcpu->arch.guest_user_asid[cpu] =

				vcpu->arch.guest_user_mm.context.asid[cpu];

			kvm_get_new_mmu_context(user_mm, cpu, vcpu);

			for_each_possible_cpu(i)

				if (i != cpu)

					vcpu->arch.guest_user_asid[cpu] = 0;

					cpu_context(i, user_mm) = 0;

			vcpu->arch.last_user_gasid = gasid;

		}

	}

arch/mips/kvm/mmu.c

+4 −4
Original line number Diff line number Diff line
@@ -15,18 +15,18 @@ 


static u32 kvm_mips_get_kernel_asid(struct kvm_vcpu *vcpu)

{

	struct mm_struct *kern_mm = &vcpu->arch.guest_kernel_mm;

	int cpu = smp_processor_id();



	return vcpu->arch.guest_kernel_asid[cpu] &

			cpu_asid_mask(&cpu_data[cpu]);

	return cpu_asid(cpu, kern_mm);

}



static u32 kvm_mips_get_user_asid(struct kvm_vcpu *vcpu)

{

	struct mm_struct *user_mm = &vcpu->arch.guest_user_mm;

	int cpu = smp_processor_id();



	return vcpu->arch.guest_user_asid[cpu] &

			cpu_asid_mask(&cpu_data[cpu]);

	return cpu_asid(cpu, user_mm);

}



static int kvm_mips_map_page(struct kvm *kvm, gfn_t gfn)