[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
Re: [PATCH] x86/svm: Don't clear clean bits on every context switch
- To: Ross Lagerwall <ross.lagerwall@xxxxxxxxxx>, <xen-devel@xxxxxxxxxxxxxxxxxxxx>
- From: Jason Andryuk <jason.andryuk@xxxxxxx>
- Date: Tue, 6 Oct 2026 12:23:49 -0400
- Arc-authentication-results: i=1; mx.microsoft.com 1; spf=pass (sender ip is 165.204.84.17) smtp.rcpttodomain=citrix.com smtp.mailfrom=amd.com; dmarc=pass (p=quarantine sp=quarantine pct=100) action=none header.from=amd.com; dkim=none (message not signed); arc=none (0)
- Arc-message-signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=microsoft.com; s=arcselector10001; h=From:Date:Subject:Message-ID:Content-Type:MIME-Version:X-MS-Exchange-AntiSpam-MessageData-ChunkCount:X-MS-Exchange-AntiSpam-MessageData-0:X-MS-Exchange-AntiSpam-MessageData-1; bh=qWLsZvlZX7pSxYLD31SMhUpsra19H0qFDFuj1hVn+6M=; b=gVdFqIYzQTOKX0nmeKvQzw15NcVkiLSVZRGkUPksAu7vXt8KNJ4h9rIAaZMiwtDZ0VyA8dxnIuW7o536KKxLrR0duJJ256PJudh/5DNBP1WW75PplXxv3nEWaErDvHwlARI3+j/buq8T2RuDmdaOIdXrY5/bBuVs9+6o6Hk8yaVnS8M1bnMVNUZa6w4ITpZQCmFrEWbEmULTa9Gtk8Tabq05yXg9Jt0Jk6ERiMjPxVJ6rv72I16fbCY7rGNeXEqtLhUGV8HNSeHY+C2SLJ1hRHGb5AYzcbD/eIzVdJffCiWVqR4yFvkh8W0Bt7/8TGKKmc2cc3ByywgtHYH9Rtf1WA==
- Arc-seal: i=1; a=rsa-sha256; s=arcselector10001; d=microsoft.com; cv=none; b=aLP3CvU5c28llY55pgkw+ZraPZm4mgxZ4we+Nk9awcNu6I55lqLzy+jdHvKm+XFqrMgWq58mWvuJ1iTENN49j1vl0rQyPNolK0yJMBzzS3i40QNHtZCNeBbOO67O7Ef7JGXzHqcjnNDqAfNqRmQGvDVbGhLrW8/lYEfVZ17DGlEqv9hqb9xXAA+USPUQnQDhdVpmQzMkokQGLgtx4qZEJbrgzbfWEZUjt3qtH41Mmd4k2zfsWNvtGWzsPNo6iZVHHCKbjw1UIozWc4dwz0uCBcXRTiLWNKWLje8ie+TYmIGO9YsYiU6P7Jxco0IB4INGhBlh/GxmVWUuW5oLeqp8vA==
- Authentication-results: eu.smtp.expurgate.cloud; dkim=pass header.s=selector1 header.d=amd.com header.i="@amd.com" header.h="From:Date:Subject:Message-ID:Content-Type:MIME-Version:X-MS-Exchange-SenderADCheck"
- Cc: Jan Beulich <jbeulich@xxxxxxxx>, Andrew Cooper <andrew.cooper3@xxxxxxxxxx>, Roger Pau Monné <roger@xxxxxxxxxxxxxx>, Teddy Astie <teddy.astie@xxxxxxxxxx>
- Delivery-date: Tue, 06 Oct 2026 17:01:04 +0000
- List-id: Xen developer discussion <xen-devel.lists.xenproject.org>
On 2026-10-06 10:48, Ross Lagerwall wrote:
Clear the cleanbits only when the VMCB is used on a different pCPU
rather than on every context switch to the vCPU. This follows the APM
guideline for when to clear the cleanbits:
"The hypervisor executes the guest on a different CPU core than one used
the last time that guest was executed."
Signed-off-by: Ross Lagerwall <ross.lagerwall@xxxxxxxxxx>
Reviewed-by: Jason Andryuk <jason.andryuk@xxxxxxx>
The other times are:
"This is the first time a particular guest is run."
The vmcb page is zeroed in alloc_vmcb().
"The hypervisor has moved the guest's VMCB to a different physical page
since the last time that guest was executed."
VMCBs aren't moved.
Regards,
Jason
|
