2014-12-22 11:25:40

by Peng Fan

[permalink] [raw]
Subject: [PATCH 1/2] arm:kvm correct prototype to make sparse happy

Warning message:
arch/arm/kvm/arm.c:85:17:
error: symbol 'kvm_get_running_vcpus' redeclared with different type
(originally declared at ./arch/arm/include/asm/kvm_host.h :190) -
different address spaces

Signed-off-by: Peng Fan <[email protected]>
CC: Gleb Natapov <[email protected]>
CC: Paolo Bonzini <[email protected]>
CC: Christoffer Dall <[email protected]>
CC: Marc Zyngier <[email protected]>
CC: Russell King <[email protected]>
---
arch/arm/include/asm/kvm_host.h | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/arm/include/asm/kvm_host.h b/arch/arm/include/asm/kvm_host.h
index 53036e2..219d025 100644
--- a/arch/arm/include/asm/kvm_host.h
+++ b/arch/arm/include/asm/kvm_host.h
@@ -187,7 +187,7 @@ static inline void kvm_arch_mmu_notifier_invalidate_page(struct kvm *kvm,
}

struct kvm_vcpu *kvm_arm_get_running_vcpu(void);
-struct kvm_vcpu __percpu **kvm_get_running_vcpus(void);
+struct kvm_vcpu * __percpu *kvm_get_running_vcpus(void);

int kvm_arm_copy_coproc_indices(struct kvm_vcpu *vcpu, u64 __user *uindices);
unsigned long kvm_arm_num_coproc_regs(struct kvm_vcpu *vcpu);
--
1.8.4


2014-12-22 11:25:45

by Peng Fan

[permalink] [raw]
Subject: [PATCH 2/2] arm:kvm remove len 8 for mmio read write buf

For arm 32 bit architecture, 8 bytes load/store operation in one instruction
will not be generated by compiler.

And before invoke mmio_read_buf, there is a piece of code:
"
len = run->mmio.len;
if (len > sizeof(unsigned long))
return -EINVAL;

data = mmio_read_buf(run->mmio.data, len);
"

This piece code also tells that len variable does not exceeds 4 bytes.
So, remove 8 bytes assign in mmio_read_buf and mmio_write_buf.

Signed-off-by: Peng Fan <[email protected]>
CC: Gleb Natapov <[email protected]>
CC: Paolo Bonzini <[email protected]>
CC: Christoffer Dall <[email protected]>
CC: Marc Zyngier <[email protected]>
CC: Russell King <[email protected]>
---
arch/arm/kvm/mmio.c | 10 ----------
1 file changed, 10 deletions(-)

diff --git a/arch/arm/kvm/mmio.c b/arch/arm/kvm/mmio.c
index 4cb5a93..953a819 100644
--- a/arch/arm/kvm/mmio.c
+++ b/arch/arm/kvm/mmio.c
@@ -30,7 +30,6 @@ static void mmio_write_buf(char *buf, unsigned int len, unsigned long data)
u8 byte;
u16 hword;
u32 word;
- u64 dword;
} tmp;

switch (len) {
@@ -46,10 +45,6 @@ static void mmio_write_buf(char *buf, unsigned int len, unsigned long data)
tmp.word = data;
datap = &tmp.word;
break;
- case 8:
- tmp.dword = data;
- datap = &tmp.dword;
- break;
}

memcpy(buf, datap, len);
@@ -61,7 +56,6 @@ static unsigned long mmio_read_buf(char *buf, unsigned int len)
union {
u16 hword;
u32 word;
- u64 dword;
} tmp;

switch (len) {
@@ -76,10 +70,6 @@ static unsigned long mmio_read_buf(char *buf, unsigned int len)
memcpy(&tmp.word, buf, len);
data = tmp.word;
break;
- case 8:
- memcpy(&tmp.dword, buf, len);
- data = tmp.dword;
- break;
}

return data;
--
1.8.4

2014-12-22 11:51:54

by Marc Zyngier

[permalink] [raw]
Subject: Re: [PATCH 2/2] arm:kvm remove len 8 for mmio read write buf

On 22/12/14 11:23, Peng Fan wrote:
> For arm 32 bit architecture, 8 bytes load/store operation in one instruction
> will not be generated by compiler.

Ever heard of lrdr/strd?

> And before invoke mmio_read_buf, there is a piece of code:
> "
> len = run->mmio.len;
> if (len > sizeof(unsigned long))
> return -EINVAL;
>
> data = mmio_read_buf(run->mmio.data, len);
> "
>
> This piece code also tells that len variable does not exceeds 4 bytes.
> So, remove 8 bytes assign in mmio_read_buf and mmio_write_buf.

NAK. This code is shared between arm and arm64. See commit f42798c.

M.

>
> Signed-off-by: Peng Fan <[email protected]>
> CC: Gleb Natapov <[email protected]>
> CC: Paolo Bonzini <[email protected]>
> CC: Christoffer Dall <[email protected]>
> CC: Marc Zyngier <[email protected]>
> CC: Russell King <[email protected]>
> ---
> arch/arm/kvm/mmio.c | 10 ----------
> 1 file changed, 10 deletions(-)
>
> diff --git a/arch/arm/kvm/mmio.c b/arch/arm/kvm/mmio.c
> index 4cb5a93..953a819 100644
> --- a/arch/arm/kvm/mmio.c
> +++ b/arch/arm/kvm/mmio.c
> @@ -30,7 +30,6 @@ static void mmio_write_buf(char *buf, unsigned int len, unsigned long data)
> u8 byte;
> u16 hword;
> u32 word;
> - u64 dword;
> } tmp;
>
> switch (len) {
> @@ -46,10 +45,6 @@ static void mmio_write_buf(char *buf, unsigned int len, unsigned long data)
> tmp.word = data;
> datap = &tmp.word;
> break;
> - case 8:
> - tmp.dword = data;
> - datap = &tmp.dword;
> - break;
> }
>
> memcpy(buf, datap, len);
> @@ -61,7 +56,6 @@ static unsigned long mmio_read_buf(char *buf, unsigned int len)
> union {
> u16 hword;
> u32 word;
> - u64 dword;
> } tmp;
>
> switch (len) {
> @@ -76,10 +70,6 @@ static unsigned long mmio_read_buf(char *buf, unsigned int len)
> memcpy(&tmp.word, buf, len);
> data = tmp.word;
> break;
> - case 8:
> - memcpy(&tmp.dword, buf, len);
> - data = tmp.dword;
> - break;
> }
>
> return data;
>


--
Jazz is not dead. It just smells funny...

2014-12-22 14:20:37

by Peng Fan

[permalink] [raw]
Subject: Re: [PATCH 2/2] arm:kvm remove len 8 for mmio read write buf

Just began learning this piece of code.
Thanks for correcting me.

On 12/22/2014 07:51 PM, Marc Zyngier wrote:
> On 22/12/14 11:23, Peng Fan wrote:
>> For arm 32 bit architecture, 8 bytes load/store operation in one instruction
>> will not be generated by compiler.
>
> Ever heard of lrdr/strd?
>
>> And before invoke mmio_read_buf, there is a piece of code:
>> "
>> len = run->mmio.len;
>> if (len > sizeof(unsigned long))
>> return -EINVAL;
>>
>> data = mmio_read_buf(run->mmio.data, len);
>> "
>>
>> This piece code also tells that len variable does not exceeds 4 bytes.
>> So, remove 8 bytes assign in mmio_read_buf and mmio_write_buf.
>
> NAK. This code is shared between arm and arm64. See commit f42798c.
>
> M.
>
>>
>> Signed-off-by: Peng Fan <[email protected]>
>> CC: Gleb Natapov <[email protected]>
>> CC: Paolo Bonzini <[email protected]>
>> CC: Christoffer Dall <[email protected]>
>> CC: Marc Zyngier <[email protected]>
>> CC: Russell King <[email protected]>
>> ---
>> arch/arm/kvm/mmio.c | 10 ----------
>> 1 file changed, 10 deletions(-)
>>
>> diff --git a/arch/arm/kvm/mmio.c b/arch/arm/kvm/mmio.c
>> index 4cb5a93..953a819 100644
>> --- a/arch/arm/kvm/mmio.c
>> +++ b/arch/arm/kvm/mmio.c
>> @@ -30,7 +30,6 @@ static void mmio_write_buf(char *buf, unsigned int len, unsigned long data)
>> u8 byte;
>> u16 hword;
>> u32 word;
>> - u64 dword;
>> } tmp;
>>
>> switch (len) {
>> @@ -46,10 +45,6 @@ static void mmio_write_buf(char *buf, unsigned int len, unsigned long data)
>> tmp.word = data;
>> datap = &tmp.word;
>> break;
>> - case 8:
>> - tmp.dword = data;
>> - datap = &tmp.dword;
>> - break;
>> }
>>
>> memcpy(buf, datap, len);
>> @@ -61,7 +56,6 @@ static unsigned long mmio_read_buf(char *buf, unsigned int len)
>> union {
>> u16 hword;
>> u32 word;
>> - u64 dword;
>> } tmp;
>>
>> switch (len) {
>> @@ -76,10 +70,6 @@ static unsigned long mmio_read_buf(char *buf, unsigned int len)
>> memcpy(&tmp.word, buf, len);
>> data = tmp.word;
>> break;
>> - case 8:
>> - memcpy(&tmp.dword, buf, len);
>> - data = tmp.dword;
>> - break;
>> }
>>
>> return data;
>>
>
>