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 4/4] powerpc/pseries/svm: Allow IOMMU to work in SVM
Date: Thu, 2 Jan 2020 14:21:06 -0800 [thread overview]
Message-ID: <20200102222106.GB5556@oc0525413822.ibm.com> (raw)
In-Reply-To: <20191216041924.42318-5-aik@ozlabs.ru>
On Mon, Dec 16, 2019 at 03:19:24PM +1100, Alexey Kardashevskiy wrote:
> H_PUT_TCE_INDIRECT uses a shared page to send up to 512 TCE to
> a hypervisor in a single hypercall.
Actually H_PUT_TCE_INDIRECT never used shared page. It would have
used shared pages if the 'shared-page' solution was accepted. :)
> This does not work for secure VMs
> as the page needs to be shared or the VM should use H_PUT_TCE instead.
Maybe you should say something like this.. ?
H_PUT_TCE_INDIRECT does not work for secure VMs, since the page
containing the TCE entries is not accessible to the hypervisor.
>
> This disables H_PUT_TCE_INDIRECT by clearing the FW_FEATURE_PUT_TCE_IND
> feature bit so SVMs will map TCEs using H_PUT_TCE.
>
> This is not a part of init_svm() as it is called too late after FW
> patching is done and may result in a warning like this:
>
> [ 3.727716] Firmware features changed after feature patching!
> [ 3.727965] WARNING: CPU: 0 PID: 1 at (...)arch/powerpc/lib/feature-fixups.c:466 check_features+0xa4/0xc0
>
> Signed-off-by: Alexey Kardashevskiy <aik@ozlabs.ru>
Reviewed-by: Ram Pai <linuxram@us.ibm.com>
> ---
> Changes:
> v2
> * new in the patchset
> ---
> arch/powerpc/platforms/pseries/firmware.c | 7 +++++++
> 1 file changed, 7 insertions(+)
>
> diff --git a/arch/powerpc/platforms/pseries/firmware.c b/arch/powerpc/platforms/pseries/firmware.c
> index d3acff23f2e3..3e49cc23a97a 100644
> --- a/arch/powerpc/platforms/pseries/firmware.c
> +++ b/arch/powerpc/platforms/pseries/firmware.c
> @@ -22,6 +22,7 @@
> #include <asm/firmware.h>
> #include <asm/prom.h>
> #include <asm/udbg.h>
> +#include <asm/svm.h>
>
> #include "pseries.h"
>
> @@ -101,6 +102,12 @@ static void __init fw_hypertas_feature_init(const char *hypertas,
> }
> }
>
> + if (is_secure_guest() &&
> + (powerpc_firmware_features & FW_FEATURE_PUT_TCE_IND)) {
> + powerpc_firmware_features &= ~FW_FEATURE_PUT_TCE_IND;
> + pr_debug("SVM: disabling PUT_TCE_IND firmware feature\n");
> + }
> +
> pr_debug(" <- fw_hypertas_feature_init()\n");
> }
>
> --
> 2.17.1
--
Ram Pai
next prev parent reply other threads:[~2020-01-02 22:24 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
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 [this message]
2020-01-03 0:08 ` David Gibson
2020-01-03 2:06 ` Ram Pai
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20200102222106.GB5556@oc0525413822.ibm.com \
--to=linuxram@us.ibm.com \
--cc=aik@ozlabs.ru \
--cc=andmike@linux.ibm.com \
--cc=bauerman@linux.ibm.com \
--cc=david@gibson.dropbear.id.au \
--cc=kvm-ppc@vger.kernel.org \
--cc=linuxppc-dev@lists.ozlabs.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).