From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jan Kiszka Subject: Re: [PATCH 3/4 V11] Add ioctl for KVMCLOCK_GUEST_STOPPED Date: Tue, 07 Feb 2012 22:28:20 +0100 Message-ID: <4F319774.4080603@web.de> References: <1328024132-7687-1-git-send-email-emunson@mgebm.net> <1328024132-7687-4-git-send-email-emunson@mgebm.net> <20120207185903.GB19800@amt.cnet> Mime-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="------------enigD8EA5235E726063E496216FD" Cc: Eric B Munson , avi@redhat.com, mingo@redhat.com, hpa@zytor.com, ryanh@linux.vnet.ibm.com, aliguori@us.ibm.com, kvm@vger.kernel.org, linux-arch@vger.kernel.org, x86@kernel.org, linux-kernel@vger.kernel.org To: Marcelo Tosatti Return-path: In-Reply-To: <20120207185903.GB19800@amt.cnet> Sender: linux-kernel-owner@vger.kernel.org List-Id: kvm.vger.kernel.org This is an OpenPGP/MIME signed message (RFC 2440 and 3156) --------------enigD8EA5235E726063E496216FD Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: quoted-printable On 2012-02-07 19:59, Marcelo Tosatti wrote: > On Tue, Jan 31, 2012 at 10:35:31AM -0500, Eric B Munson wrote: >> Now that we have a flag that will tell the guest it was suspended, cre= ate an >> interface for that communication using a KVM ioctl. >> >> Signed-off-by: Eric B Munson >> >> Cc: mingo@redhat.com >> Cc: hpa@zytor.com >> Cc: ryanh@linux.vnet.ibm.com >> Cc: aliguori@us.ibm.com >> Cc: mtosatti@redhat.com >> Cc: kvm@vger.kernel.org >> Cc: linux-arch@vger.kernel.org >> Cc: x86@kernel.org >> Cc: linux-kernel@vger.kernel.org >> --- >> Changes from V10: >> Return the ioctl to per vcpu instead of per vm >> Changes from V9: >> Use kvm_for_each_vcpu to iterate online vcpu's >> Changes from V8: >> Make KVM_GUEST_PAUSED a per vm ioctl instead of per vcpu >> Changes from V7: >> Define KVM_CAP_GUEST_PAUSED and support check >> Call mark_page_dirty () after setting PVCLOCK_GUEST_STOPPED >> Changes from V4: >> Rename KVM_GUEST_PAUSED to KVMCLOCK_GUEST_PAUSED >> Add new ioctl description to api.txt >> >> Documentation/virtual/kvm/api.txt | 13 +++++++++++++ >> arch/x86/kvm/x86.c | 21 +++++++++++++++++++++ >> include/linux/kvm.h | 3 +++ >> 3 files changed, 37 insertions(+), 0 deletions(-) >> >> diff --git a/Documentation/virtual/kvm/api.txt b/Documentation/virtual= /kvm/api.txt >> index e1d94bf..1931e5c 100644 >> --- a/Documentation/virtual/kvm/api.txt >> +++ b/Documentation/virtual/kvm/api.txt >> @@ -1491,6 +1491,19 @@ following algorithm: >> Some guests configure the LINT1 NMI input to cause a panic, aiding in= >> debugging. >> =20 >> +4.65 KVMCLOCK_GUEST_PAUSED >> + >> +Capability: KVM_CAP_GUEST_PAUSED >> +Architechtures: Any that implement pvclocks (currently x86 only) >=20 > typo: Architectures. >=20 >=20 >> +Type: vcpu ioctl >> +Parameters: None >> +Returns: 0 on success, -1 on error >> + >> +This signals to the host kernel that the specified guest is being pau= sed by >> +userspace. The host will set a flag in the pvclock structure that is= checked >> +from the soft lockup watchdog. This ioctl can be called during pause= or >> +unpause. >> + >> 5. The kvm_run structure >> =20 >> Application code obtains a pointer to the kvm_run structure by >> diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c >> index 14d6cad..c9cabba 100644 >> --- a/arch/x86/kvm/x86.c >> +++ b/arch/x86/kvm/x86.c >> @@ -2056,6 +2056,7 @@ int kvm_dev_ioctl_check_extension(long ext) >> case KVM_CAP_X86_ROBUST_SINGLESTEP: >> case KVM_CAP_XSAVE: >> case KVM_CAP_ASYNC_PF: >> + case KVM_CAP_GUEST_PAUSED: >> case KVM_CAP_GET_TSC_KHZ: >> r =3D 1; >> break; >> @@ -2503,6 +2504,22 @@ static int kvm_vcpu_ioctl_x86_set_xcrs(struct k= vm_vcpu *vcpu, >> return r; >> } >> =20 >> +/* >> + * kvm_set_guest_paused() indicates to the guest kernel that it has b= een >> + * stopped by the hypervisor. This function will be called from the = host only. >> + * EINVAL is returned when the host attempts to set the flag for a gu= est that >> + * does not support pv clocks. >> + */ >> +static int kvm_set_guest_paused(struct kvm_vcpu *vcpu) >> +{ >> + struct pvclock_vcpu_time_info *src =3D &vcpu->arch.hv_clock; >> + if (!vcpu->arch.time_page) >> + return -EINVAL; >> + src->flags |=3D PVCLOCK_GUEST_STOPPED; >> + mark_page_dirty(vcpu->kvm, vcpu->arch.time >> PAGE_SHIFT); >> + return 0; >> +} >=20 > It should also call kvm_make_request(KVM_REQ_CLOCK_UPDATE, vcpu), so > that the hv_clock is written to guest memory as soon as possible. >=20 > Please fix the comments and rebase as soon as possible, it is annoying = > that this feature is taking so long to be integrated. In addition: - Avi asked for a KVM_XXX_ naming pattern of the IOCTL, to align it with all the rest. - He even suggested KVM_CLOCK_CTRL, thus an extensible interface for passing flags via kvmclock on a per-vpcu basis. - As this is now supposed to be per-vcpu, constants should be called XXX_VCPU_STOPPED and no longer refer to "guest". Thanks, Jan --------------enigD8EA5235E726063E496216FD Content-Type: application/pgp-signature; name="signature.asc" Content-Description: OpenPGP digital signature Content-Disposition: attachment; filename="signature.asc" -----BEGIN PGP SIGNATURE----- Version: GnuPG v2.0.16 (GNU/Linux) Comment: Using GnuPG with Mozilla - http://enigmail.mozdev.org/ iEYEARECAAYFAk8xl3YACgkQitSsb3rl5xQ7gQCgj3mzymA+Hv4QfXuiVPiIiWTX ImIAoMHtQuqEUBf/NvzAyyWUH6lJ2xSy =LAK6 -----END PGP SIGNATURE----- --------------enigD8EA5235E726063E496216FD--