From: Alexander Graf <graf@amazon.com>
To: David Woodhouse <dwmw2@infradead.org>, <kvm@vger.kernel.org>
Cc: Paolo Bonzini <pbonzini@redhat.com>,
Ankur Arora <ankur.a.arora@oracle.com>,
Joao Martins <joao.m.martins@oracle.com>,
"Boris Ostrovsky" <boris.ostrovsky@oracle.com>,
Sean Christopherson <seanjc@google.com>
Subject: Re: [PATCH 02/15] KVM: x86/xen: fix Xen hypercall page msr handling
Date: Fri, 4 Dec 2020 19:26:36 +0100 [thread overview]
Message-ID: <a7eff397-4b2b-6644-8425-88bc33b3a050@amazon.com> (raw)
In-Reply-To: <20201204011848.2967588-3-dwmw2@infradead.org>
On 04.12.20 02:18, David Woodhouse wrote:
> From: Joao Martins <joao.m.martins@oracle.com>
>
> Xen usually places its MSR at 0x40000000 or 0x40000200 depending on
> whether it is running in viridian mode or not. Note that this is not
> ABI guaranteed, so it is possible for Xen to advertise the MSR some
> place else.
>
> Given the way xen_hvm_config() is handled, if the former address is
> selected, this will conflict with Hyper-V's MSR
> (HV_X64_MSR_GUEST_OS_ID) which unconditionally uses the same address.
>
> Given that the MSR location is arbitrary, move the xen_hvm_config()
> handling to the top of kvm_set_msr_common() before falling through.
>
> Signed-off-by: Joao Martins <joao.m.martins@oracle.com>
> Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>
> ---
> arch/x86/kvm/x86.c | 5 +++--
> 1 file changed, 3 insertions(+), 2 deletions(-)
>
> diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
> index c7f1ba21212e..13ba4a64f748 100644
> --- a/arch/x86/kvm/x86.c
> +++ b/arch/x86/kvm/x86.c
> @@ -3001,6 +3001,9 @@ int kvm_set_msr_common(struct kvm_vcpu *vcpu, struct msr_data *msr_info)
> u32 msr = msr_info->index;
> u64 data = msr_info->data;
>
> + if (msr && (msr == vcpu->kvm->arch.xen_hvm_config.msr))
> + return xen_hvm_config(vcpu, data);
How much of this can we handle with the MSR allow listing and MSR
trapping in user space?
Alex
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:[~2020-12-04 18:27 UTC|newest]
Thread overview: 33+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-12-04 1:18 [PATCH 00/15] KVM: Add Xen hypercall and shared info pages David Woodhouse
2020-12-04 1:18 ` [PATCH 01/15] KVM: Fix arguments to kvm_{un,}map_gfn() David Woodhouse
2020-12-04 18:27 ` Alexander Graf
2020-12-04 19:02 ` David Woodhouse
2020-12-04 1:18 ` [PATCH 02/15] KVM: x86/xen: fix Xen hypercall page msr handling David Woodhouse
2020-12-04 18:26 ` Alexander Graf [this message]
2020-12-04 18:54 ` David Woodhouse
2020-12-04 1:18 ` [PATCH 03/15] KVM: x86/xen: intercept xen hypercalls if enabled David Woodhouse
2020-12-04 18:26 ` Alexander Graf
2020-12-04 18:58 ` David Woodhouse
2020-12-05 18:42 ` Joao Martins
2020-12-05 18:51 ` David Woodhouse
2020-12-05 19:13 ` Joao Martins
2020-12-04 1:18 ` [PATCH 04/15] KVM: x86/xen: Fix coexistence of Xen and Hyper-V hypercalls David Woodhouse
2020-12-04 18:34 ` Alexander Graf
2020-12-04 19:04 ` David Woodhouse
2020-12-04 1:18 ` [PATCH 05/15] KVM: x86/xen: add KVM_XEN_HVM_SET_ATTR/KVM_XEN_HVM_GET_ATTR David Woodhouse
2020-12-04 1:18 ` [PATCH 06/15] KVM: x86/xen: latch long_mode when hypercall page is set up David Woodhouse
2020-12-04 18:38 ` Alexander Graf
2020-12-04 19:08 ` David Woodhouse
2020-12-04 1:18 ` [PATCH 07/15] KVM: x86/xen: add definitions of compat_shared_info, compat_vcpu_info David Woodhouse
2020-12-05 18:43 ` Joao Martins
2020-12-05 19:48 ` David Woodhouse
2020-12-04 1:18 ` [PATCH 08/15] KVM: x86/xen: register shared_info page David Woodhouse
2020-12-04 1:18 ` [PATCH 09/15] KVM: x86/xen: setup pvclock updates David Woodhouse
2020-12-04 1:18 ` [PATCH 10/15] xen: add wc_sec_hi to struct shared_info David Woodhouse
2020-12-04 1:18 ` [PATCH 11/15] KVM: x86/xen: update wallclock region David Woodhouse
2020-12-04 1:18 ` [PATCH 12/15] KVM: x86/xen: register vcpu info David Woodhouse
2020-12-04 1:18 ` [PATCH 13/15] KVM: x86/xen: register vcpu time info region David Woodhouse
2020-12-04 1:18 ` [PATCH 14/15] KVM: x86/xen: register runstate info David Woodhouse
2020-12-04 1:18 ` [PATCH 15/15] KVM: x86: declare Xen HVM shared info capability and add test case David Woodhouse
2020-12-04 9:11 ` [PATCH 16/15] KVM: Add documentation for Xen hypercall and shared_info updates David Woodhouse
2020-12-05 10:48 ` [PATCH 00/15] KVM: Add Xen hypercall and shared info pages David Woodhouse
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