+++ /dev/null
-From 5203012fa6045aac4b69d4e7c212e16dcf38ef10 Mon Sep 17 00:00:00 2001
-From: Xianglai Li <lixianglai@loongson.cn>
-Date: Mon, 4 May 2026 09:00:37 +0800
-Subject: LoongArch: KVM: Compile switch.S directly into the kernel
-
-From: Xianglai Li <lixianglai@loongson.cn>
-
-commit 5203012fa6045aac4b69d4e7c212e16dcf38ef10 upstream.
-
-If we directly compile the switch.S file into the kernel, the address of
-the kvm_exc_entry function will definitely be within the DMW memory area.
-Therefore, we will no longer need to perform a copy relocation of the
-kvm_exc_entry.
-
-So this patch compiles switch.S directly into the kernel, and then remove
-the copy relocation execution logic for the kvm_exc_entry function.
-
-Cc: stable@vger.kernel.org
-Signed-off-by: Xianglai Li <lixianglai@loongson.cn>
-Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>
-Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
----
- arch/loongarch/Kbuild | 2 -
- arch/loongarch/include/asm/asm-prototypes.h | 20 ++++++++++++++++
- arch/loongarch/include/asm/kvm_host.h | 3 --
- arch/loongarch/kvm/Makefile | 3 +-
- arch/loongarch/kvm/main.c | 35 ++--------------------------
- arch/loongarch/kvm/switch.S | 20 ++++++++++++----
- 6 files changed, 41 insertions(+), 42 deletions(-)
-
---- a/arch/loongarch/Kbuild
-+++ b/arch/loongarch/Kbuild
-@@ -3,7 +3,7 @@ obj-y += mm/
- obj-y += net/
- obj-y += vdso/
-
--obj-$(CONFIG_KVM) += kvm/
-+obj-$(subst m,y,$(CONFIG_KVM)) += kvm/
-
- # for cleaning
- subdir- += boot
---- a/arch/loongarch/include/asm/asm-prototypes.h
-+++ b/arch/loongarch/include/asm/asm-prototypes.h
-@@ -20,3 +20,23 @@ asmlinkage void noinstr __no_stack_prote
- struct pt_regs *regs,
- int (*fn)(void *),
- void *fn_arg);
-+
-+struct kvm_run;
-+struct kvm_vcpu;
-+struct loongarch_fpu;
-+
-+void kvm_exc_entry(void);
-+int kvm_enter_guest(struct kvm_run *run, struct kvm_vcpu *vcpu);
-+
-+void kvm_save_fpu(struct loongarch_fpu *fpu);
-+void kvm_restore_fpu(struct loongarch_fpu *fpu);
-+
-+#ifdef CONFIG_CPU_HAS_LSX
-+void kvm_save_lsx(struct loongarch_fpu *fpu);
-+void kvm_restore_lsx(struct loongarch_fpu *fpu);
-+#endif
-+
-+#ifdef CONFIG_CPU_HAS_LASX
-+void kvm_save_lasx(struct loongarch_fpu *fpu);
-+void kvm_restore_lasx(struct loongarch_fpu *fpu);
-+#endif
---- a/arch/loongarch/include/asm/kvm_host.h
-+++ b/arch/loongarch/include/asm/kvm_host.h
-@@ -85,7 +85,6 @@ struct kvm_context {
- struct kvm_world_switch {
- int (*exc_entry)(void);
- int (*enter_guest)(struct kvm_run *run, struct kvm_vcpu *vcpu);
-- unsigned long page_order;
- };
-
- #define MAX_PGTABLE_LEVELS 4
-@@ -339,8 +338,6 @@ void kvm_exc_entry(void);
- int kvm_enter_guest(struct kvm_run *run, struct kvm_vcpu *vcpu);
-
- extern unsigned long vpid_mask;
--extern const unsigned long kvm_exception_size;
--extern const unsigned long kvm_enter_guest_size;
- extern struct kvm_world_switch *kvm_loongarch_ops;
-
- #define SW_GCSR (1 << 0)
---- a/arch/loongarch/kvm/Makefile
-+++ b/arch/loongarch/kvm/Makefile
-@@ -7,11 +7,12 @@ include $(srctree)/virt/kvm/Makefile.kvm
-
- obj-$(CONFIG_KVM) += kvm.o
-
-+obj-y += switch.o
-+
- kvm-y += exit.o
- kvm-y += interrupt.o
- kvm-y += main.o
- kvm-y += mmu.o
--kvm-y += switch.o
- kvm-y += timer.o
- kvm-y += tlb.o
- kvm-y += vcpu.o
---- a/arch/loongarch/kvm/main.c
-+++ b/arch/loongarch/kvm/main.c
-@@ -340,8 +340,7 @@ void kvm_arch_disable_virtualization_cpu
-
- static int kvm_loongarch_env_init(void)
- {
-- int cpu, order, ret;
-- void *addr;
-+ int cpu, ret;
- struct kvm_context *context;
-
- vmcs = alloc_percpu(struct kvm_context);
-@@ -357,30 +356,8 @@ static int kvm_loongarch_env_init(void)
- return -ENOMEM;
- }
-
-- /*
-- * PGD register is shared between root kernel and kvm hypervisor.
-- * So world switch entry should be in DMW area rather than TLB area
-- * to avoid page fault reenter.
-- *
-- * In future if hardware pagetable walking is supported, we won't
-- * need to copy world switch code to DMW area.
-- */
-- order = get_order(kvm_exception_size + kvm_enter_guest_size);
-- addr = (void *)__get_free_pages(GFP_KERNEL, order);
-- if (!addr) {
-- free_percpu(vmcs);
-- vmcs = NULL;
-- kfree(kvm_loongarch_ops);
-- kvm_loongarch_ops = NULL;
-- return -ENOMEM;
-- }
--
-- memcpy(addr, kvm_exc_entry, kvm_exception_size);
-- memcpy(addr + kvm_exception_size, kvm_enter_guest, kvm_enter_guest_size);
-- flush_icache_range((unsigned long)addr, (unsigned long)addr + kvm_exception_size + kvm_enter_guest_size);
-- kvm_loongarch_ops->exc_entry = addr;
-- kvm_loongarch_ops->enter_guest = addr + kvm_exception_size;
-- kvm_loongarch_ops->page_order = order;
-+ kvm_loongarch_ops->exc_entry = (void *)kvm_exc_entry;
-+ kvm_loongarch_ops->enter_guest = (void *)kvm_enter_guest;
-
- vpid_mask = read_csr_gstat();
- vpid_mask = (vpid_mask & CSR_GSTAT_GIDBIT) >> CSR_GSTAT_GIDBIT_SHIFT;
-@@ -414,16 +391,10 @@ static int kvm_loongarch_env_init(void)
-
- static void kvm_loongarch_env_exit(void)
- {
-- unsigned long addr;
--
- if (vmcs)
- free_percpu(vmcs);
-
- if (kvm_loongarch_ops) {
-- if (kvm_loongarch_ops->exc_entry) {
-- addr = (unsigned long)kvm_loongarch_ops->exc_entry;
-- free_pages(addr, kvm_loongarch_ops->page_order);
-- }
- kfree(kvm_loongarch_ops);
- }
-
---- a/arch/loongarch/kvm/switch.S
-+++ b/arch/loongarch/kvm/switch.S
-@@ -4,9 +4,11 @@
- */
-
- #include <linux/linkage.h>
-+#include <linux/kvm_types.h>
- #include <asm/asm.h>
- #include <asm/asmmacro.h>
- #include <asm/loongarch.h>
-+#include <asm/page.h>
- #include <asm/regdef.h>
- #include <asm/unwind_hints.h>
-
-@@ -100,8 +102,13 @@
- * - is still in guest mode, such as pgd table/vmid registers etc,
- * - will fix with hw page walk enabled in future
- * load kvm_vcpu from reserved CSR KVM_VCPU_KS, and save a2 to KVM_TEMP_KS
-+ *
-+ * PGD register is shared between root kernel and kvm hypervisor.
-+ * So world switch entry should be in DMW area rather than TLB area
-+ * to avoid page fault re-enter.
- */
- .text
-+ .p2align PAGE_SHIFT
- .cfi_sections .debug_frame
- SYM_CODE_START(kvm_exc_entry)
- UNWIND_HINT_UNDEFINED
-@@ -190,8 +197,8 @@ ret_to_host:
- kvm_restore_host_gpr a2
- jr ra
-
--SYM_INNER_LABEL(kvm_exc_entry_end, SYM_L_LOCAL)
- SYM_CODE_END(kvm_exc_entry)
-+EXPORT_SYMBOL_FOR_KVM(kvm_exc_entry)
-
- /*
- * int kvm_enter_guest(struct kvm_run *run, struct kvm_vcpu *vcpu)
-@@ -215,8 +222,8 @@ SYM_FUNC_START(kvm_enter_guest)
- /* Save kvm_vcpu to kscratch */
- csrwr a1, KVM_VCPU_KS
- kvm_switch_to_guest
--SYM_INNER_LABEL(kvm_enter_guest_end, SYM_L_LOCAL)
- SYM_FUNC_END(kvm_enter_guest)
-+EXPORT_SYMBOL_FOR_KVM(kvm_enter_guest)
-
- SYM_FUNC_START(kvm_save_fpu)
- fpu_save_csr a0 t1
-@@ -224,6 +231,7 @@ SYM_FUNC_START(kvm_save_fpu)
- fpu_save_cc a0 t1 t2
- jr ra
- SYM_FUNC_END(kvm_save_fpu)
-+EXPORT_SYMBOL_FOR_KVM(kvm_save_fpu)
-
- SYM_FUNC_START(kvm_restore_fpu)
- fpu_restore_double a0 t1
-@@ -231,6 +239,7 @@ SYM_FUNC_START(kvm_restore_fpu)
- fpu_restore_cc a0 t1 t2
- jr ra
- SYM_FUNC_END(kvm_restore_fpu)
-+EXPORT_SYMBOL_FOR_KVM(kvm_restore_fpu)
-
- #ifdef CONFIG_CPU_HAS_LSX
- SYM_FUNC_START(kvm_save_lsx)
-@@ -239,6 +248,7 @@ SYM_FUNC_START(kvm_save_lsx)
- lsx_save_data a0 t1
- jr ra
- SYM_FUNC_END(kvm_save_lsx)
-+EXPORT_SYMBOL_FOR_KVM(kvm_save_lsx)
-
- SYM_FUNC_START(kvm_restore_lsx)
- lsx_restore_data a0 t1
-@@ -246,6 +256,7 @@ SYM_FUNC_START(kvm_restore_lsx)
- fpu_restore_csr a0 t1 t2
- jr ra
- SYM_FUNC_END(kvm_restore_lsx)
-+EXPORT_SYMBOL_FOR_KVM(kvm_restore_lsx)
- #endif
-
- #ifdef CONFIG_CPU_HAS_LASX
-@@ -255,6 +266,7 @@ SYM_FUNC_START(kvm_save_lasx)
- lasx_save_data a0 t1
- jr ra
- SYM_FUNC_END(kvm_save_lasx)
-+EXPORT_SYMBOL_FOR_KVM(kvm_save_lasx)
-
- SYM_FUNC_START(kvm_restore_lasx)
- lasx_restore_data a0 t1
-@@ -262,10 +274,8 @@ SYM_FUNC_START(kvm_restore_lasx)
- fpu_restore_csr a0 t1 t2
- jr ra
- SYM_FUNC_END(kvm_restore_lasx)
-+EXPORT_SYMBOL_FOR_KVM(kvm_restore_lasx)
- #endif
-- .section ".rodata"
--SYM_DATA(kvm_exception_size, .quad kvm_exc_entry_end - kvm_exc_entry)
--SYM_DATA(kvm_enter_guest_size, .quad kvm_enter_guest_end - kvm_enter_guest)
-
- #ifdef CONFIG_CPU_HAS_LBT
- STACK_FRAME_NON_STANDARD kvm_restore_fpu
projects / thirdparty / kernel / stable-queue.git / commitdiff
