On 07.08.2012, at 23:01, Scott Wood <scottwood@xxxxxxxxxxxxx> wrote:
> On 08/07/2012 05:57 AM, Alexander Graf wrote:
>> When we map a page that wasn't icache cleared before, do so when first
>> mapping it in KVM using the same information bits as the Linux mapping
>> logic. That way we are 100% sure that any page we map does not have stale
>> entries in the icache.
>>
>> What we really would need is a method to flush the icache only when we
>> actually map a page executable for the guest. But with the current
>> abstraction that is hard to do, and this way we don't have a huge performance
>> penalty, so better be safe now and micro optimize things later.
>>
>> Signed-off-by: Alexander Graf <agraf@xxxxxxx>
>> ---
>> arch/powerpc/include/asm/kvm_host.h | 10 ++++++++++
>> arch/powerpc/mm/mem.c | 1 +
>> 2 files changed, 11 insertions(+), 0 deletions(-)
>>
>> diff --git a/arch/powerpc/include/asm/kvm_host.h b/arch/powerpc/include/asm/kvm_host.h
>> index ed75bc9..c0a2fc1 100644
>> --- a/arch/powerpc/include/asm/kvm_host.h
>> +++ b/arch/powerpc/include/asm/kvm_host.h
>> @@ -33,6 +33,7 @@
>> #include <asm/kvm_asm.h>
>> #include <asm/processor.h>
>> #include <asm/page.h>
>> +#include <asm/cacheflush.h>
>>
>> #define KVM_MAX_VCPUS NR_CPUS
>> #define KVM_MAX_VCORES NR_CPUS
>> @@ -550,5 +551,14 @@ struct kvm_vcpu_arch {
>> #define KVM_MMIO_REG_FQPR 0x0060
>>
>> #define __KVM_HAVE_ARCH_WQP
>> +#define __KVM_HAVE_ARCH_MAP_PAGE
>> +static inline void kvm_arch_map_page(struct page *page)
>> +{
>> + /* Need to invalidate the icache for new pages */
>> + if (!test_bit(PG_arch_1, &page->flags)) {
>> + flush_dcache_icache_page(page);
>> + set_bit(PG_arch_1, &page->flags);
>> + }
>> +}
>
> Shouldn't this test CPU_FTR_COHERENT_ICACHE?
flush_icache_range checks for it a bit further down the code stream. I mostly modeled things the same way as set_pre_filter.
Alex
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