All of
 help / color / mirror / Atom feed
From: Paolo Bonzini <>
To: Sean Christopherson <>
Subject: Re: [PATCH v2 2/8] KVM: SVM: replace regs argument of __svm_vcpu_run with vcpu_svm
Date: Wed, 9 Nov 2022 11:35:41 +0100	[thread overview]
Message-ID: <> (raw)
In-Reply-To: <>

On 11/8/22 21:54, Sean Christopherson wrote:
> On Tue, Nov 08, 2022, Paolo Bonzini wrote:
>> Since registers are reachable through vcpu_svm, and we will
>> need to access more fields of that struct, pass it instead
>> of the regs[] array.
>> No functional change intended.
>> Cc:
>> Fixes: f14eec0a3203 ("KVM: SVM: move more vmentry code to assembly")
> I don't think a Fixes: tag for a pure nop patch is fair to the original commit.

That's for the sake of correct tracking in stable@, still it's not the 
right commit to point at:

- f14eec0a3203 did not move the RSB stuffing before the GSBASE restore, 
the code before was:

  #ifdef CONFIG_X86_64
  	wrmsrl(MSR_GS_BASE, svm->host.gs_base);

- anyway it wasn't really buggy at the time: it's only in -next that 
FILL_RETURN_BUFFER uses percpu data, because alternatives take care of 
the X86_FEATURE_* checks

The real reason to do all this is to access the percpu host spec_ctrl, 
which in turn is needed for retbleed.  I'll point the Fixes tag to 
a149180fbcf3 ("x86: Add magic AMD return-thunk") instead, again just for 
the sake of tracking releases that need the change to full fix retbleed.


  reply	other threads:[~2022-11-09 10:36 UTC|newest]

Thread overview: 17+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-11-08 15:15 [PATCH v2 0/8] KVM: SVM: fixes for vmentry code Paolo Bonzini
2022-11-08 15:15 ` [PATCH v2 1/8] KVM: x86: use a separate asm-offsets.c file Paolo Bonzini
2022-11-08 15:15 ` [PATCH v2 2/8] KVM: SVM: replace regs argument of __svm_vcpu_run with vcpu_svm Paolo Bonzini
2022-11-08 20:54   ` Sean Christopherson
2022-11-09 10:35     ` Paolo Bonzini [this message]
2022-11-08 15:15 ` [PATCH v2 3/8] KVM: SVM: adjust register allocation for __svm_vcpu_run Paolo Bonzini
2022-11-08 20:55   ` Sean Christopherson
2022-11-08 15:15 ` [PATCH v2 4/8] KVM: SVM: retrieve VMCB from assembly Paolo Bonzini
2022-11-09  0:53   ` Sean Christopherson
2022-11-09  9:09     ` Paolo Bonzini
2022-11-08 15:15 ` [PATCH v2 5/8] KVM: SVM: move guest vmsave/vmload to assembly Paolo Bonzini
2022-11-08 15:15 ` [PATCH v2 6/8] KVM: SVM: restore host save area from assembly Paolo Bonzini
2022-11-08 15:15 ` [PATCH v2 7/8] KVM: SVM: move MSR_IA32_SPEC_CTRL save/restore to assembly Paolo Bonzini
2022-11-09  1:14   ` Sean Christopherson
2022-11-09  9:29     ` Paolo Bonzini
2022-11-08 15:15 ` [PATCH v2 8/8] x86, KVM: remove unnecessary argument to x86_virt_spec_ctrl and callers Paolo Bonzini
2022-11-08 19:43 ` [PATCH v2 0/8] KVM: SVM: fixes for vmentry code Nathan Chancellor

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:

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \ \ \ \ \ \ \ \ \ \ \ \

* 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.