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Message-ID: <877e8f3xvk.fsf@morokweng.localdomain>
Date: Thu, 18 Jul 2019 17:12:47 -0300
From: Thiago Jung Bauermann <bauerman@...ux.ibm.com>
To: Alexey Kardashevskiy <aik@...abs.ru>
Cc: linuxppc-dev@...ts.ozlabs.org, linux-kernel@...r.kernel.org,
Anshuman Khandual <anshuman.linux@...il.com>,
Benjamin Herrenschmidt <benh@...nel.crashing.org>,
Christoph Hellwig <hch@....de>,
Michael Ellerman <mpe@...erman.id.au>,
Mike Anderson <andmike@...ux.ibm.com>,
Paul Mackerras <paulus@...ba.org>,
Ram Pai <linuxram@...ibm.com>,
Claudio Carvalho <cclaudio@...ux.ibm.com>
Subject: Re: [PATCH v2 04/13] powerpc/pseries/svm: Add helpers for UV_SHARE_PAGE and UV_UNSHARE_PAGE
Hello Alexey,
Thanks for your review!
Alexey Kardashevskiy <aik@...abs.ru> writes:
> On 13/07/2019 16:00, Thiago Jung Bauermann wrote:
>> From: Ram Pai <linuxram@...ibm.com>
>>
>> These functions are used when the guest wants to grant the hypervisor
>> access to certain pages.
>>
>> Signed-off-by: Ram Pai <linuxram@...ibm.com>
>> Signed-off-by: Thiago Jung Bauermann <bauerman@...ux.ibm.com>
>> ---
>> arch/powerpc/include/asm/ultravisor-api.h | 2 ++
>> arch/powerpc/include/asm/ultravisor.h | 15 +++++++++++++++
>> 2 files changed, 17 insertions(+)
>>
>> diff --git a/arch/powerpc/include/asm/ultravisor-api.h b/arch/powerpc/include/asm/ultravisor-api.h
>> index fe9a0d8d7673..c7513bbadf57 100644
>> --- a/arch/powerpc/include/asm/ultravisor-api.h
>> +++ b/arch/powerpc/include/asm/ultravisor-api.h
>> @@ -25,6 +25,8 @@
>> #define UV_UNREGISTER_MEM_SLOT 0xF124
>> #define UV_PAGE_IN 0xF128
>> #define UV_PAGE_OUT 0xF12C
>> +#define UV_SHARE_PAGE 0xF130
>> +#define UV_UNSHARE_PAGE 0xF134
>> #define UV_PAGE_INVAL 0xF138
>> #define UV_SVM_TERMINATE 0xF13C
>> diff --git a/arch/powerpc/include/asm/ultravisor.h
>> b/arch/powerpc/include/asm/ultravisor.h
>> index f5dc5af739b8..f7418b663a0e 100644
>> --- a/arch/powerpc/include/asm/ultravisor.h
>> +++ b/arch/powerpc/include/asm/ultravisor.h
>> @@ -91,6 +91,21 @@ static inline int uv_svm_terminate(u64 lpid)
>> return ucall(UV_SVM_TERMINATE, retbuf, lpid);
>> }
>> +
>> +static inline int uv_share_page(u64 pfn, u64 npages)
>> +{
>> + unsigned long retbuf[UCALL_BUFSIZE];
>> +
>> + return ucall(UV_SHARE_PAGE, retbuf, pfn, npages);
>
>
> What is in that retbuf? Can you pass NULL instead?
I think so, that buffer isn't used actually. Claudio is working on a
ucall_norets() which doesn't take the buffer and I can switch to that.
--
Thiago Jung Bauermann
IBM Linux Technology Center
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