Messages in this thread | | | Date | Mon, 22 Dec 2014 11:51:27 +0000 | From | Marc Zyngier <> | Subject | Re: [PATCH 2/2] arm:kvm remove len 8 for mmio read write buf |
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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 <van.freenix@gmail.com> > CC: Gleb Natapov <gleb@kernel.org> > CC: Paolo Bonzini <pbonzini@redhat.com> > CC: Christoffer Dall <christoffer.dall@linaro.org> > CC: Marc Zyngier <marc.zyngier@arm.com> > CC: Russell King <linux@arm.linux.org.uk> > --- > 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...
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