From: "Tian, Kevin" <kevin.tian@intel.com>
To: Roger Pau Monne <roger.pau@citrix.com>,
"xen-devel@lists.xenproject.org" <xen-devel@lists.xenproject.org>
Cc: Andrew Cooper <andrew.cooper3@citrix.com>, Wei Liu <wl@xen.org>,
Jan Beulich <jbeulich@suse.com>,
"Nakajima, Jun" <jun.nakajima@intel.com>
Subject: Re: [Xen-devel] [PATCH v3 3/4] x86/nvmx: split updating RVI from SVI in nvmx_update_apicv
Date: Fri, 27 Mar 2020 02:21:46 +0000 [thread overview]
Message-ID: <AADFC41AFE54684AB9EE6CBC0274A5D19D7EC9E0@SHSMSX104.ccr.corp.intel.com> (raw)
In-Reply-To: <20200326152720.36970-4-roger.pau@citrix.com>
> From: Roger Pau Monne <roger.pau@citrix.com>
> Sent: Thursday, March 26, 2020 11:27 PM
>
> Updating SVI is required when an interrupt has been injected using the
> Ack on exit VMEXIT feature, so that the in service interrupt in the
> GUEST_INTR_STATUS matches the vector that is signaled in
> VM_EXIT_INTR_INFO.
>
> Updating RVI however is not tied to the Ack on exit feature, as it
> signals the next vector to be injected, and hence should always be
> updated to the next pending vector, regardless of whether Ack on exit
> is enabled.
>
> When not using the Ack on exit feature preserve the previous vector in
> SVI, so that it's not lost when RVI is updated to contain the pending
> vector to inject.
>
> Signed-off-by: Roger Pau Monné <roger.pau@citrix.com>
Reviewed-by: Kevin Tian <kevin.tian@intel.com>, with one small comment:
> ---
> Changes since v2:
> - Return early if the exit reason != EXTERNAL_INTERRUPT.
> - Reduce the number of vmwrites by accumulating the changes to a
> local variable which is flushed at the end of the function.
> - Attempt to preserve the exiting SVI if Ack on exit is not enabled.
> ---
> xen/arch/x86/hvm/vmx/vvmx.c | 33 ++++++++++++++++++++++++---------
> 1 file changed, 24 insertions(+), 9 deletions(-)
>
> diff --git a/xen/arch/x86/hvm/vmx/vvmx.c b/xen/arch/x86/hvm/vmx/vvmx.c
> index 1753005c91..39fb553590 100644
> --- a/xen/arch/x86/hvm/vmx/vvmx.c
> +++ b/xen/arch/x86/hvm/vmx/vvmx.c
> @@ -1384,28 +1384,43 @@ static void nvmx_update_apicv(struct vcpu *v)
> struct nestedvmx *nvmx = &vcpu_2_nvmx(v);
> unsigned long reason = get_vvmcs(v, VM_EXIT_REASON);
> unsigned long intr_info = get_vvmcs(v, VM_EXIT_INTR_INFO);
> + unsigned long status;
> + int rvi;
>
> - if ( reason == EXIT_REASON_EXTERNAL_INTERRUPT &&
> - nvmx->intr.source == hvm_intsrc_lapic &&
> + if ( reason != EXIT_REASON_EXTERNAL_INTERRUPT )
> + return;
can we also exit if source is not lapic? as we discussed in another
thread, the whole logic here is only for lapic not others...
Thanks
Kevin
> +
> + if ( nvmx->intr.source == hvm_intsrc_lapic &&
> (intr_info & INTR_INFO_VALID_MASK) )
> {
> - uint16_t status;
> - uint32_t rvi, ppr;
> - uint32_t vector = intr_info & 0xff;
> + uint32_t ppr;
> + unsigned int vector = intr_info & INTR_INFO_VECTOR_MASK;
> struct vlapic *vlapic = vcpu_vlapic(v);
>
> + /*
> + * Update SVI to record the current in service interrupt that's
> + * signaled in EXIT_INTR_INFO.
> + */
> vlapic_ack_pending_irq(v, vector, 1);
>
> ppr = vlapic_set_ppr(vlapic);
> WARN_ON((ppr & 0xf0) != (vector & 0xf0));
>
> status = vector << VMX_GUEST_INTR_STATUS_SVI_OFFSET;
> - rvi = vlapic_has_pending_irq(v);
> - if ( rvi != -1 )
> - status |= rvi & VMX_GUEST_INTR_STATUS_SUBFIELD_BITMASK;
> + }
> + else
> + /* Keep previous SVI if there's any. */
> + __vmread(GUEST_INTR_STATUS, &status);
>
> - __vmwrite(GUEST_INTR_STATUS, status);
> + rvi = vlapic_has_pending_irq(v);
> + if ( rvi != -1 )
> + {
> + status &= ~VMX_GUEST_INTR_STATUS_SUBFIELD_BITMASK
> + status |= rvi & VMX_GUEST_INTR_STATUS_SUBFIELD_BITMASK;
> }
> +
> + if ( status )
> + __vmwrite(GUEST_INTR_STATUS, status);
> }
>
> static void virtual_vmexit(struct cpu_user_regs *regs)
> --
> 2.26.0
next prev parent reply other threads:[~2020-03-27 2:22 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-03-26 15:27 [Xen-devel] [PATCH v3 0/4] x86/nvmx: fixes for interrupt injection Roger Pau Monne
2020-03-26 15:27 ` [Xen-devel] [PATCH v3 1/4] Revert "x86/vvmx: fix virtual interrupt injection when Ack on exit control is used" Roger Pau Monne
2020-03-26 15:27 ` [Xen-devel] [PATCH v3 2/4] x86/nvmx: only update SVI when using Ack on exit Roger Pau Monne
2020-03-26 15:27 ` [Xen-devel] [PATCH v3 3/4] x86/nvmx: split updating RVI from SVI in nvmx_update_apicv Roger Pau Monne
2020-03-27 2:21 ` Tian, Kevin [this message]
2020-03-27 9:48 ` Roger Pau Monné
2020-03-26 15:27 ` [Xen-devel] [PATCH v3 4/4] x86/nvmx: update exit bitmap when using virtual interrupt delivery Roger Pau Monne
2020-03-27 2:22 ` Tian, Kevin
2020-03-26 15:41 ` [Xen-devel] [PATCH v3 0/4] x86/nvmx: fixes for interrupt injection Jan Beulich
2020-03-26 15:49 ` Roger Pau Monné
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=AADFC41AFE54684AB9EE6CBC0274A5D19D7EC9E0@SHSMSX104.ccr.corp.intel.com \
--to=kevin.tian@intel.com \
--cc=andrew.cooper3@citrix.com \
--cc=jbeulich@suse.com \
--cc=jun.nakajima@intel.com \
--cc=roger.pau@citrix.com \
--cc=wl@xen.org \
--cc=xen-devel@lists.xenproject.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).