All of lore.kernel.org
 help / color / mirror / Atom feed
From: Michael Ellerman <patch-notifications@ellerman.id.au>
To: Alexey Kardashevskiy <aik@ozlabs.ru>, linuxppc-dev@lists.ozlabs.org
Cc: Frederic Barrat <fbarrat@linux.ibm.com>,
	kvm-ppc@vger.kernel.org, Fabiano Rosas <farosas@linux.ibm.com>
Subject: Re: [PATCH kernel v2] KVM: PPC: Book3s: Retire H_PUT_TCE/etc real mode handlers
Date: Tue, 24 May 2022 20:51:51 +1000	[thread overview]
Message-ID: <165338951112.1711920.752815379112806107.b4-ty@ellerman.id.au> (raw)
In-Reply-To: <20220506053755.3820702-1-aik@ozlabs.ru>

On Fri, 6 May 2022 15:37:55 +1000, Alexey Kardashevskiy wrote:
> LoPAPR defines guest visible IOMMU with hypercalls to use it -
> H_PUT_TCE/etc. Implemented first on POWER7 where hypercalls would trap
> in the KVM in the real mode (with MMU off). The problem with the real mode
> is some memory is not available and some API usage crashed the host but
> enabling MMU was an expensive operation.
> 
> The problems with the real mode handlers are:
> 1. Occasionally these cannot complete the request so the code is
> copied+modified to work in the virtual mode, very little is shared;
> 2. The real mode handlers have to be linked into vmlinux to work;
> 3. An exception in real mode immediately reboots the machine.
> 
> [...]

Applied to powerpc/topic/ppc-kvm.

[1/1] KVM: PPC: Book3s: Retire H_PUT_TCE/etc real mode handlers
      https://git.kernel.org/powerpc/c/cad32d9d42e8e6a659786f8a730b221a9fbee227

cheers

WARNING: multiple messages have this Message-ID (diff)
From: Michael Ellerman <patch-notifications@ellerman.id.au>
To: Alexey Kardashevskiy <aik@ozlabs.ru>, linuxppc-dev@lists.ozlabs.org
Cc: Frederic Barrat <fbarrat@linux.ibm.com>,
	kvm-ppc@vger.kernel.org, Fabiano Rosas <farosas@linux.ibm.com>
Subject: Re: [PATCH kernel v2] KVM: PPC: Book3s: Retire H_PUT_TCE/etc real mode handlers
Date: Tue, 24 May 2022 10:51:51 +0000	[thread overview]
Message-ID: <165338951112.1711920.752815379112806107.b4-ty@ellerman.id.au> (raw)
In-Reply-To: <20220506053755.3820702-1-aik@ozlabs.ru>

On Fri, 6 May 2022 15:37:55 +1000, Alexey Kardashevskiy wrote:
> LoPAPR defines guest visible IOMMU with hypercalls to use it -
> H_PUT_TCE/etc. Implemented first on POWER7 where hypercalls would trap
> in the KVM in the real mode (with MMU off). The problem with the real mode
> is some memory is not available and some API usage crashed the host but
> enabling MMU was an expensive operation.
> 
> The problems with the real mode handlers are:
> 1. Occasionally these cannot complete the request so the code is
> copied+modified to work in the virtual mode, very little is shared;
> 2. The real mode handlers have to be linked into vmlinux to work;
> 3. An exception in real mode immediately reboots the machine.
> 
> [...]

Applied to powerpc/topic/ppc-kvm.

[1/1] KVM: PPC: Book3s: Retire H_PUT_TCE/etc real mode handlers
      https://git.kernel.org/powerpc/c/cad32d9d42e8e6a659786f8a730b221a9fbee227

cheers

  reply	other threads:[~2022-05-24 10:54 UTC|newest]

Thread overview: 4+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-05-06  5:37 [PATCH kernel v2] KVM: PPC: Book3s: Retire H_PUT_TCE/etc real mode handlers Alexey Kardashevskiy
2022-05-06  5:37 ` Alexey Kardashevskiy
2022-05-24 10:51 ` Michael Ellerman [this message]
2022-05-24 10:51   ` Michael Ellerman

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=165338951112.1711920.752815379112806107.b4-ty@ellerman.id.au \
    --to=patch-notifications@ellerman.id.au \
    --cc=aik@ozlabs.ru \
    --cc=farosas@linux.ibm.com \
    --cc=fbarrat@linux.ibm.com \
    --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 an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.