KVM: Move x86's version of struct kvm_mmu_memory_cache to common code

Move x86's 'struct kvm_mmu_memory_cache' to common code in anticipation of moving the entire x86 implementation code to common KVM and reusing it for arm64 and MIPS. Add a new architecture specific asm/kvm_types.h to control the existence and parameters of the struct. The new header is needed to avoid a chicken-and-egg problem with asm/kvm_host.h as all architectures define instances of the struct in their vCPU structs. Add an asm-generic version of kvm_types.h to avoid having empty files on PPC and s390 in the long term, and for arm64 and mips in the short term.

Sean Christopherson committed 6 years ago

Commit 2aa9c191 parent 94ce87e8 files · +35 −13Browse files

Unified · Split

8 files

arch/arm64/include/asm/Kbuild +1 −0
arch/mips/include/asm/Kbuild +1 −0
arch/powerpc/include/asm/Kbuild +1 −0
arch/s390/include/asm/Kbuild +1 −0
arch/x86/include/asm/kvm_host.h +0 −13
arch/x86/include/asm/kvm_types.h +7 −0
include/asm-generic/kvm_types.h +5 −0
include/linux/kvm_types.h +19 −0

arch/arm64/include/asm/Kbuild+1−0

@@ -1,5 +1,6 @@
1	1	# SPDX-License-Identifier: GPL-2.0
2	2	generic-y += early_ioremap.h
	3	+generic-y += kvm_types.h
3	4	generic-y += local64.h
4	5	generic-y += mcs_spinlock.h
5	6	generic-y += qrwlock.h

arch/mips/include/asm/Kbuild+1−0

@@ -5,6 +5,7 @@ generated-y += syscall_table_64_n32.h · 4 unmodified lines
5	5	generated-y += syscall_table_64_n64.h
6	6	generated-y += syscall_table_64_o32.h
7	7	generic-y += export.h
	8	+generic-y += kvm_types.h
8	9	generic-y += local64.h
9	10	generic-y += mcs_spinlock.h
10	11	generic-y += parport.h

arch/powerpc/include/asm/Kbuild+1−0

@@ -4,6 +4,7 @@ generated-y += syscall_table_64.h · 3 unmodified lines
4	4	generated-y += syscall_table_c32.h
5	5	generated-y += syscall_table_spu.h
6	6	generic-y += export.h
	7	+generic-y += kvm_types.h
7	8	generic-y += local64.h
8	9	generic-y += mcs_spinlock.h
9	10	generic-y += vtime.h

arch/s390/include/asm/Kbuild+1−0

@@ -6,5 +6,6 @@ generated-y += unistd_nr.h · 5 unmodified lines
6	6
7	7	generic-y += asm-offsets.h
8	8	generic-y += export.h
	9	+generic-y += kvm_types.h
9	10	generic-y += local64.h
10	11	generic-y += mcs_spinlock.h

arch/x86/include/asm/kvm_host.h+0−13

@@ -193,8 +193,6 @@ struct x86_exception; · 192 unmodified lines
193	193	enum x86_intercept;
194	194	enum x86_intercept_stage;
195	195
196		−#define KVM_NR_MEM_OBJS 40
197		−
198	196	#define KVM_NR_DB_REGS 4
199	197
200	198	#define DR6_BD (1 << 13)
@@ -245,17 +243,6 @@ enum x86_intercept_stage; · 44 unmodified lines
245	243
246	244	struct kvm_kernel_irq_routing_entry;
247	245
248		−/*
249		− * We don't want allocation failures within the mmu code, so we preallocate
250		− * enough memory for a single page fault in a cache.
251		− */
252		−struct kvm_mmu_memory_cache {
253		− int nobjs;
254		− gfp_t gfp_zero;
255		− struct kmem_cache *kmem_cache;
256		− void *objects[KVM_NR_MEM_OBJS];
257		−};
258		−
259	246	/*
260	247	* the pages used as guest page table on soft mmu are tracked by
261	248	* kvm_memory_slot.arch.gfn_track which is 16 bits, so the role bits used

arch/x86/include/asm/kvm_types.h+7−0

@@ -0,0 +1,7 @@
	1	+/* SPDX-License-Identifier: GPL-2.0 */
	2	+#ifndef _ASM_X86_KVM_TYPES_H
	3	+#define _ASM_X86_KVM_TYPES_H
	4	+
	5	+#define KVM_ARCH_NR_OBJS_PER_MEMORY_CACHE 40
	6	+
	7	+#endif /* _ASM_X86_KVM_TYPES_H */

include/asm-generic/kvm_types.h+5−0

@@ -0,0 +1,5 @@
	1	+/* SPDX-License-Identifier: GPL-2.0 */
	2	+#ifndef _ASM_GENERIC_KVM_TYPES_H
	3	+#define _ASM_GENERIC_KVM_TYPES_H
	4	+
	5	+#endif

include/linux/kvm_types.h+19−0

@@ -20,6 +20,8 @@ enum kvm_mr_change; · 19 unmodified lines
20	20
21	21	#include <linux/types.h>
22	22
	23	+#include <asm/kvm_types.h>
	24	+
23	25	/*
24	26	* Address types:
25	27	*
@@ -58,4 +60,21 @@ struct gfn_to_pfn_cache { · 32 unmodified lines
58	60	bool dirty;
59	61	};
60	62
	63	+#ifdef KVM_ARCH_NR_OBJS_PER_MEMORY_CACHE
	64	+/*
	65	+ * Memory caches are used to preallocate memory ahead of various MMU flows,
	66	+ * e.g. page fault handlers. Gracefully handling allocation failures deep in
	67	+ * MMU flows is problematic, as is triggering reclaim, I/O, etc... while
	68	+ * holding MMU locks. Note, these caches act more like prefetch buffers than
	69	+ * classical caches, i.e. objects are not returned to the cache on being freed.
	70	+ */
	71	+struct kvm_mmu_memory_cache {
	72	+ int nobjs;
	73	+ gfp_t gfp_zero;
	74	+ struct kmem_cache *kmem_cache;
	75	+ void *objects[KVM_ARCH_NR_OBJS_PER_MEMORY_CACHE];
	76	+};
	77	+#endif
	78	+
	79	+
61	80	#endif /* __KVM_TYPES_H__ */