2020-04-26 12:41:20

by Tianjia Zhang

[permalink] [raw]
Subject: [PATCH v3 7/7] KVM: MIPS: clean up redundant kvm_run parameters in assembly

In the current kvm version, 'kvm_run' has been included in the 'kvm_vcpu'
structure. Earlier than historical reasons, many kvm-related function
parameters retain the 'kvm_run' and 'kvm_vcpu' parameters at the same time.
This patch does a unified cleanup of these remaining redundant parameters.

Signed-off-by: Tianjia Zhang <[email protected]>
---
arch/mips/include/asm/kvm_host.h | 4 ++--
arch/mips/kvm/entry.c | 15 +++++----------
arch/mips/kvm/mips.c | 3 ++-
arch/mips/kvm/trap_emul.c | 2 +-
arch/mips/kvm/vz.c | 2 +-
5 files changed, 11 insertions(+), 15 deletions(-)

diff --git a/arch/mips/include/asm/kvm_host.h b/arch/mips/include/asm/kvm_host.h
index 971439297cea..db915c55166d 100644
--- a/arch/mips/include/asm/kvm_host.h
+++ b/arch/mips/include/asm/kvm_host.h
@@ -310,7 +310,7 @@ struct kvm_mmu_memory_cache {
#define KVM_MIPS_GUEST_TLB_SIZE 64
struct kvm_vcpu_arch {
void *guest_ebase;
- int (*vcpu_run)(struct kvm_run *run, struct kvm_vcpu *vcpu);
+ int (*vcpu_run)(struct kvm_vcpu *vcpu);

/* Host registers preserved across guest mode execution */
unsigned long host_stack;
@@ -821,7 +821,7 @@ int kvm_mips_emulation_init(struct kvm_mips_callbacks **install_callbacks);
/* Debug: dump vcpu state */
int kvm_arch_vcpu_dump_regs(struct kvm_vcpu *vcpu);

-extern int kvm_mips_handle_exit(struct kvm_run *run, struct kvm_vcpu *vcpu);
+extern int kvm_mips_handle_exit(struct kvm_vcpu *vcpu);

/* Building of entry/exception code */
int kvm_mips_entry_setup(void);
diff --git a/arch/mips/kvm/entry.c b/arch/mips/kvm/entry.c
index 16e1c93b484f..e3f29af3b6cd 100644
--- a/arch/mips/kvm/entry.c
+++ b/arch/mips/kvm/entry.c
@@ -204,7 +204,7 @@ static inline void build_set_exc_base(u32 **p, unsigned int reg)
* Assemble the start of the vcpu_run function to run a guest VCPU. The function
* conforms to the following prototype:
*
- * int vcpu_run(struct kvm_run *run, struct kvm_vcpu *vcpu);
+ * int vcpu_run(struct kvm_vcpu *vcpu);
*
* The exit from the guest and return to the caller is handled by the code
* generated by kvm_mips_build_ret_to_host().
@@ -217,8 +217,7 @@ void *kvm_mips_build_vcpu_run(void *addr)
unsigned int i;

/*
- * A0: run
- * A1: vcpu
+ * A0: vcpu
*/

/* k0/k1 not being used in host kernel context */
@@ -237,10 +236,10 @@ void *kvm_mips_build_vcpu_run(void *addr)
kvm_mips_build_save_scratch(&p, V1, K1);

/* VCPU scratch register has pointer to vcpu */
- UASM_i_MTC0(&p, A1, scratch_vcpu[0], scratch_vcpu[1]);
+ UASM_i_MTC0(&p, A0, scratch_vcpu[0], scratch_vcpu[1]);

/* Offset into vcpu->arch */
- UASM_i_ADDIU(&p, K1, A1, offsetof(struct kvm_vcpu, arch));
+ UASM_i_ADDIU(&p, K1, A0, offsetof(struct kvm_vcpu, arch));

/*
* Save the host stack to VCPU, used for exception processing
@@ -628,10 +627,7 @@ void *kvm_mips_build_exit(void *addr)
/* Now that context has been saved, we can use other registers */

/* Restore vcpu */
- UASM_i_MFC0(&p, S1, scratch_vcpu[0], scratch_vcpu[1]);
-
- /* Restore run (vcpu->run) */
- UASM_i_LW(&p, S0, offsetof(struct kvm_vcpu, run), S1);
+ UASM_i_MFC0(&p, S0, scratch_vcpu[0], scratch_vcpu[1]);

/*
* Save Host level EPC, BadVaddr and Cause to VCPU, useful to process
@@ -793,7 +789,6 @@ void *kvm_mips_build_exit(void *addr)
* with this in the kernel
*/
uasm_i_move(&p, A0, S0);
- uasm_i_move(&p, A1, S1);
UASM_i_LA(&p, T9, (unsigned long)kvm_mips_handle_exit);
uasm_i_jalr(&p, RA, T9);
UASM_i_ADDIU(&p, SP, SP, -CALLFRAME_SIZ);
diff --git a/arch/mips/kvm/mips.c b/arch/mips/kvm/mips.c
index 9710477a9827..32850470c037 100644
--- a/arch/mips/kvm/mips.c
+++ b/arch/mips/kvm/mips.c
@@ -1186,8 +1186,9 @@ static void kvm_mips_set_c0_status(void)
/*
* Return value is in the form (errcode<<2 | RESUME_FLAG_HOST | RESUME_FLAG_NV)
*/
-int kvm_mips_handle_exit(struct kvm_run *run, struct kvm_vcpu *vcpu)
+int kvm_mips_handle_exit(struct kvm_vcpu *vcpu)
{
+ struct kvm_run *run = vcpu->run;
u32 cause = vcpu->arch.host_cp0_cause;
u32 exccode = (cause >> CAUSEB_EXCCODE) & 0x1f;
u32 __user *opc = (u32 __user *) vcpu->arch.pc;
diff --git a/arch/mips/kvm/trap_emul.c b/arch/mips/kvm/trap_emul.c
index d822f3aee3dc..04c864cc356a 100644
--- a/arch/mips/kvm/trap_emul.c
+++ b/arch/mips/kvm/trap_emul.c
@@ -1238,7 +1238,7 @@ static int kvm_trap_emul_vcpu_run(struct kvm_vcpu *vcpu)
*/
kvm_mips_suspend_mm(cpu);

- r = vcpu->arch.vcpu_run(vcpu->run, vcpu);
+ r = vcpu->arch.vcpu_run(vcpu);

/* We may have migrated while handling guest exits */
cpu = smp_processor_id();
diff --git a/arch/mips/kvm/vz.c b/arch/mips/kvm/vz.c
index 94f1d23828e3..c5878fa0636d 100644
--- a/arch/mips/kvm/vz.c
+++ b/arch/mips/kvm/vz.c
@@ -3152,7 +3152,7 @@ static int kvm_vz_vcpu_run(struct kvm_vcpu *vcpu)
kvm_vz_vcpu_load_tlb(vcpu, cpu);
kvm_vz_vcpu_load_wired(vcpu);

- r = vcpu->arch.vcpu_run(vcpu->run, vcpu);
+ r = vcpu->arch.vcpu_run(vcpu);

kvm_vz_vcpu_save_wired(vcpu);

--
2.17.1


2020-04-27 03:46:29

by Huacai Chen

[permalink] [raw]
Subject: Re: [PATCH v3 7/7] KVM: MIPS: clean up redundant kvm_run parameters in assembly

Hi, Tianjia,

On Sun, Apr 26, 2020 at 8:40 PM Tianjia Zhang
<[email protected]> wrote:
>
> In the current kvm version, 'kvm_run' has been included in the 'kvm_vcpu'
> structure. Earlier than historical reasons, many kvm-related function
> parameters retain the 'kvm_run' and 'kvm_vcpu' parameters at the same time.
> This patch does a unified cleanup of these remaining redundant parameters.
>
> Signed-off-by: Tianjia Zhang <[email protected]>
> ---
> arch/mips/include/asm/kvm_host.h | 4 ++--
> arch/mips/kvm/entry.c | 15 +++++----------
> arch/mips/kvm/mips.c | 3 ++-
> arch/mips/kvm/trap_emul.c | 2 +-
> arch/mips/kvm/vz.c | 2 +-
> 5 files changed, 11 insertions(+), 15 deletions(-)
>
> diff --git a/arch/mips/include/asm/kvm_host.h b/arch/mips/include/asm/kvm_host.h
> index 971439297cea..db915c55166d 100644
> --- a/arch/mips/include/asm/kvm_host.h
> +++ b/arch/mips/include/asm/kvm_host.h
> @@ -310,7 +310,7 @@ struct kvm_mmu_memory_cache {
> #define KVM_MIPS_GUEST_TLB_SIZE 64
> struct kvm_vcpu_arch {
> void *guest_ebase;
> - int (*vcpu_run)(struct kvm_run *run, struct kvm_vcpu *vcpu);
> + int (*vcpu_run)(struct kvm_vcpu *vcpu);
>
> /* Host registers preserved across guest mode execution */
> unsigned long host_stack;
> @@ -821,7 +821,7 @@ int kvm_mips_emulation_init(struct kvm_mips_callbacks **install_callbacks);
> /* Debug: dump vcpu state */
> int kvm_arch_vcpu_dump_regs(struct kvm_vcpu *vcpu);
>
> -extern int kvm_mips_handle_exit(struct kvm_run *run, struct kvm_vcpu *vcpu);
> +extern int kvm_mips_handle_exit(struct kvm_vcpu *vcpu);
>
> /* Building of entry/exception code */
> int kvm_mips_entry_setup(void);
> diff --git a/arch/mips/kvm/entry.c b/arch/mips/kvm/entry.c
> index 16e1c93b484f..e3f29af3b6cd 100644
> --- a/arch/mips/kvm/entry.c
> +++ b/arch/mips/kvm/entry.c
> @@ -204,7 +204,7 @@ static inline void build_set_exc_base(u32 **p, unsigned int reg)
> * Assemble the start of the vcpu_run function to run a guest VCPU. The function
> * conforms to the following prototype:
> *
> - * int vcpu_run(struct kvm_run *run, struct kvm_vcpu *vcpu);
> + * int vcpu_run(struct kvm_vcpu *vcpu);
> *
> * The exit from the guest and return to the caller is handled by the code
> * generated by kvm_mips_build_ret_to_host().
> @@ -217,8 +217,7 @@ void *kvm_mips_build_vcpu_run(void *addr)
> unsigned int i;
>
> /*
> - * A0: run
> - * A1: vcpu
> + * A0: vcpu
> */
>
> /* k0/k1 not being used in host kernel context */
> @@ -237,10 +236,10 @@ void *kvm_mips_build_vcpu_run(void *addr)
> kvm_mips_build_save_scratch(&p, V1, K1);
>
> /* VCPU scratch register has pointer to vcpu */
> - UASM_i_MTC0(&p, A1, scratch_vcpu[0], scratch_vcpu[1]);
> + UASM_i_MTC0(&p, A0, scratch_vcpu[0], scratch_vcpu[1]);
>
> /* Offset into vcpu->arch */
> - UASM_i_ADDIU(&p, K1, A1, offsetof(struct kvm_vcpu, arch));
> + UASM_i_ADDIU(&p, K1, A0, offsetof(struct kvm_vcpu, arch));
>
> /*
> * Save the host stack to VCPU, used for exception processing
> @@ -628,10 +627,7 @@ void *kvm_mips_build_exit(void *addr)
> /* Now that context has been saved, we can use other registers */
>
> /* Restore vcpu */
> - UASM_i_MFC0(&p, S1, scratch_vcpu[0], scratch_vcpu[1]);
> -
> - /* Restore run (vcpu->run) */
> - UASM_i_LW(&p, S0, offsetof(struct kvm_vcpu, run), S1);
> + UASM_i_MFC0(&p, S0, scratch_vcpu[0], scratch_vcpu[1]);
>
> /*
> * Save Host level EPC, BadVaddr and Cause to VCPU, useful to process
> @@ -793,7 +789,6 @@ void *kvm_mips_build_exit(void *addr)
> * with this in the kernel
> */
> uasm_i_move(&p, A0, S0);
> - uasm_i_move(&p, A1, S1);
> UASM_i_LA(&p, T9, (unsigned long)kvm_mips_handle_exit);
> uasm_i_jalr(&p, RA, T9);
> UASM_i_ADDIU(&p, SP, SP, -CALLFRAME_SIZ);
I think uasm_i_move(&p, K1, S1) in kvm_mips_build_ret_from_exit() and
UASM_i_MTC0(&p, S1, scratch_vcpu[0], scratch_vcpu[1]) in
kvm_mips_build_ret_to_guest() should also be changed.

> diff --git a/arch/mips/kvm/mips.c b/arch/mips/kvm/mips.c
> index 9710477a9827..32850470c037 100644
> --- a/arch/mips/kvm/mips.c
> +++ b/arch/mips/kvm/mips.c
> @@ -1186,8 +1186,9 @@ static void kvm_mips_set_c0_status(void)
> /*
> * Return value is in the form (errcode<<2 | RESUME_FLAG_HOST | RESUME_FLAG_NV)
> */
> -int kvm_mips_handle_exit(struct kvm_run *run, struct kvm_vcpu *vcpu)
> +int kvm_mips_handle_exit(struct kvm_vcpu *vcpu)
> {
> + struct kvm_run *run = vcpu->run;
> u32 cause = vcpu->arch.host_cp0_cause;
> u32 exccode = (cause >> CAUSEB_EXCCODE) & 0x1f;
> u32 __user *opc = (u32 __user *) vcpu->arch.pc;
> diff --git a/arch/mips/kvm/trap_emul.c b/arch/mips/kvm/trap_emul.c
> index d822f3aee3dc..04c864cc356a 100644
> --- a/arch/mips/kvm/trap_emul.c
> +++ b/arch/mips/kvm/trap_emul.c
> @@ -1238,7 +1238,7 @@ static int kvm_trap_emul_vcpu_run(struct kvm_vcpu *vcpu)
> */
> kvm_mips_suspend_mm(cpu);
>
> - r = vcpu->arch.vcpu_run(vcpu->run, vcpu);
> + r = vcpu->arch.vcpu_run(vcpu);
>
> /* We may have migrated while handling guest exits */
> cpu = smp_processor_id();
> diff --git a/arch/mips/kvm/vz.c b/arch/mips/kvm/vz.c
> index 94f1d23828e3..c5878fa0636d 100644
> --- a/arch/mips/kvm/vz.c
> +++ b/arch/mips/kvm/vz.c
> @@ -3152,7 +3152,7 @@ static int kvm_vz_vcpu_run(struct kvm_vcpu *vcpu)
> kvm_vz_vcpu_load_tlb(vcpu, cpu);
> kvm_vz_vcpu_load_wired(vcpu);
>
> - r = vcpu->arch.vcpu_run(vcpu->run, vcpu);
> + r = vcpu->arch.vcpu_run(vcpu);
>
> kvm_vz_vcpu_save_wired(vcpu);
>
> --
> 2.17.1
>

Regards,
Huacai

2020-04-27 04:16:55

by Tianjia Zhang

[permalink] [raw]
Subject: Re: [PATCH v3 7/7] KVM: MIPS: clean up redundant kvm_run parameters in assembly



On 2020/4/27 11:51, Huacai Chen wrote:
> Hi, Tianjia,
>
> On Sun, Apr 26, 2020 at 8:40 PM Tianjia Zhang
> <[email protected]> wrote:
>>
>> In the current kvm version, 'kvm_run' has been included in the 'kvm_vcpu'
>> structure. Earlier than historical reasons, many kvm-related function
>> parameters retain the 'kvm_run' and 'kvm_vcpu' parameters at the same time.
>> This patch does a unified cleanup of these remaining redundant parameters.
>>
>> Signed-off-by: Tianjia Zhang <[email protected]>
>> ---
>> arch/mips/include/asm/kvm_host.h | 4 ++--
>> arch/mips/kvm/entry.c | 15 +++++----------
>> arch/mips/kvm/mips.c | 3 ++-
>> arch/mips/kvm/trap_emul.c | 2 +-
>> arch/mips/kvm/vz.c | 2 +-
>> 5 files changed, 11 insertions(+), 15 deletions(-)
>>
>> diff --git a/arch/mips/include/asm/kvm_host.h b/arch/mips/include/asm/kvm_host.h
>> index 971439297cea..db915c55166d 100644
>> --- a/arch/mips/include/asm/kvm_host.h
>> +++ b/arch/mips/include/asm/kvm_host.h
>> @@ -310,7 +310,7 @@ struct kvm_mmu_memory_cache {
>> #define KVM_MIPS_GUEST_TLB_SIZE 64
>> struct kvm_vcpu_arch {
>> void *guest_ebase;
>> - int (*vcpu_run)(struct kvm_run *run, struct kvm_vcpu *vcpu);
>> + int (*vcpu_run)(struct kvm_vcpu *vcpu);
>>
>> /* Host registers preserved across guest mode execution */
>> unsigned long host_stack;
>> @@ -821,7 +821,7 @@ int kvm_mips_emulation_init(struct kvm_mips_callbacks **install_callbacks);
>> /* Debug: dump vcpu state */
>> int kvm_arch_vcpu_dump_regs(struct kvm_vcpu *vcpu);
>>
>> -extern int kvm_mips_handle_exit(struct kvm_run *run, struct kvm_vcpu *vcpu);
>> +extern int kvm_mips_handle_exit(struct kvm_vcpu *vcpu);
>>
>> /* Building of entry/exception code */
>> int kvm_mips_entry_setup(void);
>> diff --git a/arch/mips/kvm/entry.c b/arch/mips/kvm/entry.c
>> index 16e1c93b484f..e3f29af3b6cd 100644
>> --- a/arch/mips/kvm/entry.c
>> +++ b/arch/mips/kvm/entry.c
>> @@ -204,7 +204,7 @@ static inline void build_set_exc_base(u32 **p, unsigned int reg)
>> * Assemble the start of the vcpu_run function to run a guest VCPU. The function
>> * conforms to the following prototype:
>> *
>> - * int vcpu_run(struct kvm_run *run, struct kvm_vcpu *vcpu);
>> + * int vcpu_run(struct kvm_vcpu *vcpu);
>> *
>> * The exit from the guest and return to the caller is handled by the code
>> * generated by kvm_mips_build_ret_to_host().
>> @@ -217,8 +217,7 @@ void *kvm_mips_build_vcpu_run(void *addr)
>> unsigned int i;
>>
>> /*
>> - * A0: run
>> - * A1: vcpu
>> + * A0: vcpu
>> */
>>
>> /* k0/k1 not being used in host kernel context */
>> @@ -237,10 +236,10 @@ void *kvm_mips_build_vcpu_run(void *addr)
>> kvm_mips_build_save_scratch(&p, V1, K1);
>>
>> /* VCPU scratch register has pointer to vcpu */
>> - UASM_i_MTC0(&p, A1, scratch_vcpu[0], scratch_vcpu[1]);
>> + UASM_i_MTC0(&p, A0, scratch_vcpu[0], scratch_vcpu[1]);
>>
>> /* Offset into vcpu->arch */
>> - UASM_i_ADDIU(&p, K1, A1, offsetof(struct kvm_vcpu, arch));
>> + UASM_i_ADDIU(&p, K1, A0, offsetof(struct kvm_vcpu, arch));
>>
>> /*
>> * Save the host stack to VCPU, used for exception processing
>> @@ -628,10 +627,7 @@ void *kvm_mips_build_exit(void *addr)
>> /* Now that context has been saved, we can use other registers */
>>
>> /* Restore vcpu */
>> - UASM_i_MFC0(&p, S1, scratch_vcpu[0], scratch_vcpu[1]);
>> -
>> - /* Restore run (vcpu->run) */
>> - UASM_i_LW(&p, S0, offsetof(struct kvm_vcpu, run), S1);
>> + UASM_i_MFC0(&p, S0, scratch_vcpu[0], scratch_vcpu[1]);
>>
>> /*
>> * Save Host level EPC, BadVaddr and Cause to VCPU, useful to process
>> @@ -793,7 +789,6 @@ void *kvm_mips_build_exit(void *addr)
>> * with this in the kernel
>> */
>> uasm_i_move(&p, A0, S0);
>> - uasm_i_move(&p, A1, S1);
>> UASM_i_LA(&p, T9, (unsigned long)kvm_mips_handle_exit);
>> uasm_i_jalr(&p, RA, T9);
>> UASM_i_ADDIU(&p, SP, SP, -CALLFRAME_SIZ);
> I think uasm_i_move(&p, K1, S1) in kvm_mips_build_ret_from_exit() and
> UASM_i_MTC0(&p, S1, scratch_vcpu[0], scratch_vcpu[1]) in
> kvm_mips_build_ret_to_guest() should also be changed.
>

Your statement is correct, this is my omission, I will fix it in the
next version of the patch, thanks for your review.

Thanks and best,
Tianjia

>> diff --git a/arch/mips/kvm/mips.c b/arch/mips/kvm/mips.c
>> index 9710477a9827..32850470c037 100644
>> --- a/arch/mips/kvm/mips.c
>> +++ b/arch/mips/kvm/mips.c
>> @@ -1186,8 +1186,9 @@ static void kvm_mips_set_c0_status(void)
>> /*
>> * Return value is in the form (errcode<<2 | RESUME_FLAG_HOST | RESUME_FLAG_NV)
>> */
>> -int kvm_mips_handle_exit(struct kvm_run *run, struct kvm_vcpu *vcpu)
>> +int kvm_mips_handle_exit(struct kvm_vcpu *vcpu)
>> {
>> + struct kvm_run *run = vcpu->run;
>> u32 cause = vcpu->arch.host_cp0_cause;
>> u32 exccode = (cause >> CAUSEB_EXCCODE) & 0x1f;
>> u32 __user *opc = (u32 __user *) vcpu->arch.pc;
>> diff --git a/arch/mips/kvm/trap_emul.c b/arch/mips/kvm/trap_emul.c
>> index d822f3aee3dc..04c864cc356a 100644
>> --- a/arch/mips/kvm/trap_emul.c
>> +++ b/arch/mips/kvm/trap_emul.c
>> @@ -1238,7 +1238,7 @@ static int kvm_trap_emul_vcpu_run(struct kvm_vcpu *vcpu)
>> */
>> kvm_mips_suspend_mm(cpu);
>>
>> - r = vcpu->arch.vcpu_run(vcpu->run, vcpu);
>> + r = vcpu->arch.vcpu_run(vcpu);
>>
>> /* We may have migrated while handling guest exits */
>> cpu = smp_processor_id();
>> diff --git a/arch/mips/kvm/vz.c b/arch/mips/kvm/vz.c
>> index 94f1d23828e3..c5878fa0636d 100644
>> --- a/arch/mips/kvm/vz.c
>> +++ b/arch/mips/kvm/vz.c
>> @@ -3152,7 +3152,7 @@ static int kvm_vz_vcpu_run(struct kvm_vcpu *vcpu)
>> kvm_vz_vcpu_load_tlb(vcpu, cpu);
>> kvm_vz_vcpu_load_wired(vcpu);
>>
>> - r = vcpu->arch.vcpu_run(vcpu->run, vcpu);
>> + r = vcpu->arch.vcpu_run(vcpu);
>>
>> kvm_vz_vcpu_save_wired(vcpu);
>>
>> --
>> 2.17.1
>>
>
> Regards,
> Huacai
>