From: Siddharth Chandrasekaran <sidcha@amazon.de>
To: Vitaly Kuznetsov <vkuznets@redhat.com>
Cc: Alexander Graf <graf@amazon.com>,
Evgeny Iakovlev <eyakovl@amazon.de>,
Liran Alon <liran@amazon.com>,
Ioannis Aslanidis <iaslan@amazon.de>,
<linux-hyperv@vger.kernel.org>, <linux-kernel@vger.kernel.org>,
<kvm@vger.kernel.org>, "K. Y. Srinivasan" <kys@microsoft.com>,
Haiyang Zhang <haiyangz@microsoft.com>,
Stephen Hemminger <sthemmin@microsoft.com>,
Wei Liu <wei.liu@kernel.org>,
Thomas Gleixner <tglx@linutronix.de>,
Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>,
<x86@kernel.org>, "H. Peter Anvin" <hpa@zytor.com>,
Paolo Bonzini <pbonzini@redhat.com>,
"Sean Christopherson" <seanjc@google.com>,
Wanpeng Li <wanpengli@tencent.com>,
"Jim Mattson" <jmattson@google.com>,
Joerg Roedel <joro@8bytes.org>
Subject: Re: [PATCH v2 2/4] KVM: hyper-v: Collect hypercall params into struct
Date: Tue, 13 Apr 2021 16:11:17 +0200 [thread overview]
Message-ID: <20210413141117.GA29970@uc8bbc9586ea454.ant.amazon.com> (raw)
In-Reply-To: <87v98q5m0y.fsf@vitty.brq.redhat.com>
On Tue, Apr 13, 2021 at 03:53:01PM +0200, Vitaly Kuznetsov wrote:
> Siddharth Chandrasekaran <sidcha@amazon.de> writes:
> > As of now there are 7 parameters (and flags) that are used in various
> > hyper-v hypercall handlers. There are 6 more input/output parameters
> > passed from XMM registers which are to be added in an upcoming patch.
> >
> > To make passing arguments to the handlers more readable, capture all
> > these parameters into a single structure.
> >
> > Cc: Alexander Graf <graf@amazon.com>
> > Cc: Evgeny Iakovlev <eyakovl@amazon.de>
> > Signed-off-by: Siddharth Chandrasekaran <sidcha@amazon.de>
> > ---
> > arch/x86/kvm/hyperv.c | 147 +++++++++++++++++++++++-------------------
> > 1 file changed, 79 insertions(+), 68 deletions(-)
> >
> > diff --git a/arch/x86/kvm/hyperv.c b/arch/x86/kvm/hyperv.c
> > index f98370a39936..8f6babd1ea0d 100644
> > --- a/arch/x86/kvm/hyperv.c
> > +++ b/arch/x86/kvm/hyperv.c
> > @@ -1623,7 +1623,18 @@ static __always_inline unsigned long *sparse_set_to_vcpu_mask(
> > return vcpu_bitmap;
> > }
> >
> > -static u64 kvm_hv_flush_tlb(struct kvm_vcpu *vcpu, u64 ingpa, u16 rep_cnt, bool ex)
> > +struct kvm_hv_hcall {
> > + u64 param;
> > + u64 ingpa;
> > + u64 outgpa;
> > + u16 code;
> > + u16 rep_cnt;
> > + u16 rep_idx;
> > + bool fast;
> > + bool rep;
> > +};
> > +
> > +static u64 kvm_hv_flush_tlb(struct kvm_vcpu *vcpu, struct kvm_hv_hcall *hc, bool ex)
>
> Nitpick: Would it make sense to also pack the fact that we're dealing
> with a hypercall using ExProcessorMasks into 'struct kvm_hv_hcall' and
> get rid of 'bool ex' parameter for both kvm_hv_flush_tlb() and
> kvm_hv_send_ipi()? 'struct kvm_hv_hcall' is already a synthetic
> aggregator for input and output so adding some other information there
> may not be that big of a stretch...
The other members of the struct are all hypercall parameters (or flags)
while the 'bool ex' is our way of handling ExProcessorMasks within the
same method.
Besides, in kvm_hv_hypercall() passing it as a 3rd argument looks
better than setting 'hc.ex = true' and than immediately calling the
method :-).
> > {
> > struct kvm *kvm = vcpu->kvm;
> > struct kvm_vcpu_hv *hv_vcpu = to_hv_vcpu(vcpu);
> > @@ -1638,7 +1649,7 @@ static u64 kvm_hv_flush_tlb(struct kvm_vcpu *vcpu, u64 ingpa, u16 rep_cnt, bool
> > bool all_cpus;
> >
> > if (!ex) {
> > - if (unlikely(kvm_read_guest(kvm, ingpa, &flush, sizeof(flush))))
> > + if (unlikely(kvm_read_guest(kvm, hc->ingpa, &flush, sizeof(flush))))
> > return HV_STATUS_INVALID_HYPERCALL_INPUT;
> >
> > trace_kvm_hv_flush_tlb(flush.processor_mask,
> > @@ -1657,7 +1668,7 @@ static u64 kvm_hv_flush_tlb(struct kvm_vcpu *vcpu, u64 ingpa, u16 rep_cnt, bool
> > all_cpus = (flush.flags & HV_FLUSH_ALL_PROCESSORS) ||
> > flush.processor_mask == 0;
> > } else {
> > - if (unlikely(kvm_read_guest(kvm, ingpa, &flush_ex,
> > + if (unlikely(kvm_read_guest(kvm, hc->ingpa, &flush_ex,
> > sizeof(flush_ex))))
> > return HV_STATUS_INVALID_HYPERCALL_INPUT;
> >
> > @@ -1679,8 +1690,8 @@ static u64 kvm_hv_flush_tlb(struct kvm_vcpu *vcpu, u64 ingpa, u16 rep_cnt, bool
> >
> > if (!all_cpus &&
> > kvm_read_guest(kvm,
> > - ingpa + offsetof(struct hv_tlb_flush_ex,
> > - hv_vp_set.bank_contents),
> > + hc->ingpa + offsetof(struct hv_tlb_flush_ex,
> > + hv_vp_set.bank_contents),
> > sparse_banks,
> > sparse_banks_len))
> > return HV_STATUS_INVALID_HYPERCALL_INPUT;
> > @@ -1700,9 +1711,9 @@ static u64 kvm_hv_flush_tlb(struct kvm_vcpu *vcpu, u64 ingpa, u16 rep_cnt, bool
> > NULL, vcpu_mask, &hv_vcpu->tlb_flush);
> >
> > ret_success:
> > - /* We always do full TLB flush, set rep_done = rep_cnt. */
> > + /* We always do full TLB flush, set rep_done = hc->rep_cnt. */
>
> Nitpicking: I'd suggest we word it a bit differently:
>
> "We always do full TLB flush, set 'Reps completed' = 'Rep Count'."
>
> so it matches TLFS rather than KVM internals.
Makes sense. Changed.
Thanks for your reviews.
~ Sid.
Amazon Development Center Germany GmbH
Krausenstr. 38
10117 Berlin
Geschaeftsfuehrung: Christian Schlaeger, Jonathan Weiss
Eingetragen am Amtsgericht Charlottenburg unter HRB 149173 B
Sitz: Berlin
Ust-ID: DE 289 237 879
next prev parent reply other threads:[~2021-04-13 14:11 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-04-12 17:00 [PATCH v2 0/4] Add support for XMM fast hypercalls Siddharth Chandrasekaran
2021-04-12 17:00 ` [PATCH v2 1/4] KVM: x86: Move FPU register accessors into fpu.h Siddharth Chandrasekaran
2021-04-13 13:40 ` Vitaly Kuznetsov
2021-04-13 13:46 ` Siddharth Chandrasekaran
2021-04-12 17:00 ` [PATCH v2 2/4] KVM: hyper-v: Collect hypercall params into struct Siddharth Chandrasekaran
2021-04-13 13:53 ` Vitaly Kuznetsov
2021-04-13 14:11 ` Siddharth Chandrasekaran [this message]
2021-04-12 17:00 ` [PATCH v2 3/4] KVM: x86: kvm_hv_flush_tlb use inputs from XMM registers Siddharth Chandrasekaran
2021-04-12 20:13 ` Wei Liu
2021-04-13 9:09 ` Siddharth Chandrasekaran
2021-04-13 14:09 ` Vitaly Kuznetsov
2021-04-13 21:07 ` Siddharth Chandrasekaran
2021-04-12 17:00 ` [PATCH v2 4/4] KVM: hyper-v: Advertise support for fast XMM hypercalls Siddharth Chandrasekaran
2021-04-12 20:14 ` Wei Liu
2021-04-13 9:11 ` Siddharth Chandrasekaran
2021-04-13 14:26 ` Vitaly Kuznetsov
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=20210413141117.GA29970@uc8bbc9586ea454.ant.amazon.com \
--to=sidcha@amazon.de \
--cc=bp@alien8.de \
--cc=eyakovl@amazon.de \
--cc=graf@amazon.com \
--cc=haiyangz@microsoft.com \
--cc=hpa@zytor.com \
--cc=iaslan@amazon.de \
--cc=jmattson@google.com \
--cc=joro@8bytes.org \
--cc=kvm@vger.kernel.org \
--cc=kys@microsoft.com \
--cc=linux-hyperv@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=liran@amazon.com \
--cc=mingo@redhat.com \
--cc=pbonzini@redhat.com \
--cc=seanjc@google.com \
--cc=sthemmin@microsoft.com \
--cc=tglx@linutronix.de \
--cc=vkuznets@redhat.com \
--cc=wanpengli@tencent.com \
--cc=wei.liu@kernel.org \
--cc=x86@kernel.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).