From: James Hogan <james.hogan@imgtec.com>
To: Paolo Bonzini <pbonzini@redhat.com>
Cc: linux-mips@linux-mips.org, kvm@vger.kernel.org,
"Radim Krčmář" <rkrcmar@redhat.com>,
"Ralf Baechle" <ralf@linux-mips.org>,
"Jonathan Corbet" <corbet@lwn.net>,
linux-doc@vger.kernel.org
Subject: Re: [PATCH 11/32] KVM: MIPS: Add VZ capability
Date: Fri, 3 Mar 2017 12:37:24 +0000 [thread overview]
Message-ID: <20170303123724.GD2878@jhogan-linux.le.imgtec.org> (raw)
In-Reply-To: <20170302223407.GQ996@jhogan-linux.le.imgtec.org>
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On Thu, Mar 02, 2017 at 10:34:07PM +0000, James Hogan wrote:
> I suppose the exception is T&E. It shouldn't assume that just because VZ
> is available that T&E isn't (even if that is the case right now). It
> could always just try KVM_CREATE_VM with kvm type 0 and detect the error
> I suppose, but capabilities are nicer.
>
> Maybe I'll redefine KVM_CAP_MIPS_VZ a bit, such that the value returned
> + 1 is a bitmask of supported kvm types:
> has T&E = !!( (v + 1) & BIT(KVM_VM_MIPS_TE) )
> has VZ = !!( (v + 1) & BIT(KVM_VM_MIPS_VZ) )
>
> That way old kernels which return 0 are consistent, and other
> implementations could be added if really necessary without confusing
> userland (but fingers crossed it'll never ever be necessary).
Actually I think the way I had designed KVM_CAP_MIPS_VZ is fine. I had
defined it as an enumeration rather than a mask because it isn't
expected you'd have more than one hardware virtualisation type able to
run on a particular core.
Whether T&E is still supported is I think better exposed by a new
KVM_CAP_MIPS_TE capability, indicating whether T&E is exposed when
KVM_CAP_MIPS_VZ is also set.
It would be set to 1 on new kernels whenever T&E is supported.
For compatibility with older kernels, userland would be expected to
determine whether T&E is present by:
check(KVM_CAP_MIPS_VZ) == 0 || check(KVM_CAP_MIPS_TE) != 0
Old userland that doesn't check KVM_CAP_MIPS_TE would just hit an EINVAL
from KVM_CREATE_VM if T&E isn't supported.
Cheers
James
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next prev parent reply other threads:[~2017-03-03 12:37 UTC|newest]
Thread overview: 39+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-03-02 9:36 [PATCH 0/32] KVM: MIPS: Add VZ support James Hogan
2017-03-02 9:36 ` [PATCH 1/32] MIPS: Add defs & probing of UFR James Hogan
2017-03-02 9:36 ` [PATCH 2/32] MIPS: Separate MAAR V bit into VL and VH for XPA James Hogan
2017-03-02 9:36 ` [PATCH 3/32] MIPS: Probe guest CP0_UserLocal James Hogan
2017-03-02 9:36 ` [PATCH 4/32] MIPS: Probe guest MVH James Hogan
2017-03-02 9:36 ` [PATCH 5/32] MIPS: Add some missing guest CP0 accessors & defs James Hogan
2017-03-02 9:36 ` [PATCH 6/32] MIPS: asm/tlb.h: Add UNIQUE_GUEST_ENTRYHI() macro James Hogan
2017-03-02 9:36 ` [PATCH 7/32] KVM: MIPS/Emulate: De-duplicate MMIO emulation James Hogan
2017-03-02 9:36 ` [PATCH 8/32] KVM: MIPS/Emulate: Implement 64-bit " James Hogan
2017-03-02 9:36 ` [PATCH 9/32] KVM: MIPS: Update kvm_lose_fpu() for VZ James Hogan
2017-03-02 9:36 ` [PATCH 10/32] KVM: MIPS: Extend counters & events for VZ GExcCodes James Hogan
2017-03-02 9:36 ` [PATCH 11/32] KVM: MIPS: Add VZ capability James Hogan
2017-03-02 10:59 ` Paolo Bonzini
2017-03-02 11:39 ` James Hogan
2017-03-02 12:20 ` Paolo Bonzini
2017-03-02 22:34 ` James Hogan
2017-03-03 12:37 ` James Hogan [this message]
2017-03-03 12:41 ` Paolo Bonzini
2017-03-02 9:36 ` [PATCH 12/32] KVM: MIPS: Add 64BIT capability James Hogan
2017-03-02 9:36 ` [PATCH 13/32] KVM: MIPS: Init timer frequency from callback James Hogan
2017-03-02 9:36 ` [PATCH 14/32] KVM: MIPS: Add callback to check extension James Hogan
2017-03-02 9:36 ` [PATCH 15/32] KVM: MIPS: Add hardware_{enable,disable} callback James Hogan
2017-03-02 9:36 ` [PATCH 16/32] KVM: MIPS: Add guest exit exception callback James Hogan
2017-03-02 9:36 ` [PATCH 17/32] KVM: MIPS: Abstract guest CP0 register access for VZ James Hogan
2017-03-02 9:36 ` [PATCH 18/32] KVM: MIPS/Entry: Update entry code to support VZ James Hogan
2017-03-02 9:36 ` [PATCH 19/32] KVM: MIPS/TLB: Add VZ TLB management James Hogan
2017-03-02 9:36 ` [PATCH 20/32] KVM: MIPS/Emulate: Update CP0_Compare emulation for VZ James Hogan
2017-03-02 9:36 ` [PATCH 21/32] KVM: MIPS/Emulate: Drop CACHE " James Hogan
2017-03-02 9:36 ` [PATCH 22/32] KVM: MIPS: Update exit handler " James Hogan
2017-03-02 9:36 ` [PATCH 23/32] KVM: MIPS: Implement VZ support James Hogan
2017-03-02 9:36 ` [PATCH 24/32] KVM: MIPS: Add VZ support to build system James Hogan
2017-03-02 9:36 ` [PATCH 25/32] KVM: MIPS/VZ: Support guest CP0_BadInstr[P] James Hogan
2017-03-02 9:36 ` [PATCH 26/32] KVM: MIPS/VZ: Support guest CP0_[X]ContextConfig James Hogan
2017-03-02 9:36 ` [PATCH 27/32] KVM: MIPS/VZ: Support guest segmentation control James Hogan
2017-03-02 9:36 ` [PATCH 28/32] KVM: MIPS/VZ: Support guest hardware page table walker James Hogan
2017-03-02 9:36 ` [PATCH 29/32] KVM: MIPS/VZ: Support guest load-linked bit James Hogan
2017-03-02 9:36 ` [PATCH 30/32] KVM: MIPS/VZ: Emulate MAARs when necessary James Hogan
2017-03-02 9:36 ` [PATCH 31/32] KVM: MIPS/VZ: Support hardware guest timer James Hogan
2017-03-02 9:36 ` [PATCH 32/32] KVM: MIPS/VZ: Trace guest mode changes James Hogan
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