From: Ram Pai <linuxram@us.ibm.com>
To: Alexey Kardashevskiy <aik@ozlabs.ru>
Cc: Michael Anderson <andmike@linux.ibm.com>,
kvm-ppc@vger.kernel.org, linuxppc-dev@lists.ozlabs.org,
Thiago Jung Bauermann <bauerman@linux.ibm.com>,
David Gibson <david@gibson.dropbear.id.au>
Subject: Re: [PATCH kernel v2 3/4] powerpc/pseries/iommu: Separate FW_FEATURE_MULTITCE to put/stuff features
Date: Thu, 2 Jan 2020 14:24:32 -0800 [thread overview]
Message-ID: <20200102222432.GC5556@oc0525413822.ibm.com> (raw)
In-Reply-To: <20191216041924.42318-4-aik@ozlabs.ru>
On Mon, Dec 16, 2019 at 03:19:23PM +1100, Alexey Kardashevskiy wrote:
> H_PUT_TCE_INDIRECT allows packing up to 512 TCE updates into a single
> hypercall; H_STUFF_TCE can clear lots in a single hypercall too.
>
> However, unlike H_STUFF_TCE (which writes the same TCE to all entries),
> H_PUT_TCE_INDIRECT uses a 4K page with new TCEs. In a secure VM
> environment this means sharing a secure VM page with a hypervisor which
> we would rather avoid.
>
> This splits the FW_FEATURE_MULTITCE feature into FW_FEATURE_PUT_TCE_IND
Can FW_FEATURE_PUT_TCE_IND be made FW_FEATURE_PUT_TCE_INDIRECT?
It conveys the meaning a bit better than FW_FEATURE_PUT_TCE_IND.
This patch is a good optimization.
Reviewed-by: Ram Pai <linuxram@us.ibm.com>
Thanks,
RP
> --
snip..
> 2.17.1
--
Ram Pai
next prev parent reply other threads:[~2020-01-02 22:28 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-12-16 4:19 [PATCH kernel v2 0/4] Enable IOMMU support for pseries Secure VMs Alexey Kardashevskiy
2019-12-16 4:19 ` [PATCH kernel v2 1/4] Revert "powerpc/pseries/iommu: Don't use dma_iommu_ops on secure guests" Alexey Kardashevskiy
2019-12-16 22:58 ` Thiago Jung Bauermann
2020-01-06 23:33 ` Michael Ellerman
2019-12-16 4:19 ` [PATCH kernel v2 2/4] powerpc/pseries: Allow not having ibm, hypertas-functions::hcall-multi-tce for DDW Alexey Kardashevskiy
2019-12-16 23:07 ` Thiago Jung Bauermann
2019-12-17 0:09 ` [PATCH kernel v2 2/4] powerpc/pseries: Allow not having ibm,hypertas-functions::hcall-multi-tce " Alexey Kardashevskiy
2019-12-17 2:06 ` [PATCH kernel v2 2/4] powerpc/pseries: Allow not having ibm, hypertas-functions::hcall-multi-tce " Thiago Jung Bauermann
2020-01-02 22:02 ` [PATCH kernel v2 2/4] powerpc/pseries: Allow not having ibm,hypertas-functions::hcall-multi-tce " Ram Pai
2019-12-16 4:19 ` [PATCH kernel v2 3/4] powerpc/pseries/iommu: Separate FW_FEATURE_MULTITCE to put/stuff features Alexey Kardashevskiy
2019-12-16 23:19 ` Thiago Jung Bauermann
2020-01-02 22:24 ` Ram Pai [this message]
2019-12-16 4:19 ` [PATCH kernel v2 4/4] powerpc/pseries/svm: Allow IOMMU to work in SVM Alexey Kardashevskiy
2019-12-16 23:23 ` Thiago Jung Bauermann
2020-01-02 22:21 ` Ram Pai
2020-01-03 0:08 ` David Gibson
2020-01-03 2:06 ` Ram Pai
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