From: Tao Su <tao1.su@linux.intel.com>
To: Gerd Hoffmann <kraxel@redhat.com>
Cc: kvm@vger.kernel.org, Sean Christopherson <seanjc@google.com>,
Paolo Bonzini <pbonzini@redhat.com>,
Thomas Gleixner <tglx@linutronix.de>,
Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>,
Dave Hansen <dave.hansen@linux.intel.com>,
"maintainer:X86 ARCHITECTURE (32-BIT AND 64-BIT)"
<x86@kernel.org>, "H. Peter Anvin" <hpa@zytor.com>,
"open list:X86 ARCHITECTURE (32-BIT AND 64-BIT)"
<linux-kernel@vger.kernel.org>
Subject: Re: [PATCH 1/3] kvm: wire up KVM_CAP_VM_GPA_BITS for x86
Date: Mon, 4 Mar 2024 16:59:32 +0800 [thread overview]
Message-ID: <ZeWNdBSWVTAwtLyI@linux.bj.intel.com> (raw)
In-Reply-To: <vlr6f5dnyhb6aw5si6m4vxqemwoyg7lrti7pdy4jzatady5mgr@bv44qwgk6ppu>
On Mon, Mar 04, 2024 at 09:43:53AM +0100, Gerd Hoffmann wrote:
> > > + kvm_caps.guest_phys_bits = boot_cpu_data.x86_phys_bits;
> >
> > When KeyID_bits is non-zero, MAXPHYADDR != boot_cpu_data.x86_phys_bits
> > here, you can check in detect_tme().
>
> from detect_tme():
>
> /*
> * KeyID bits effectively lower the number of physical address
> * bits. Update cpuinfo_x86::x86_phys_bits accordingly.
> */
> c->x86_phys_bits -= keyid_bits;
>
> This looks like x86_phys_bits gets adjusted if needed.
If TDP is enabled and supports 5-level, we want kvm_caps.guest_phys_bits=52,
but c->x86_phys_bits!=52 here. Maybe we need to set kvm_caps.guest_phys_bits
according to whether TDP is enabled or not, like leaf 0x80000008 in
__do_cpuid_func().
Thanks,
Tao
next prev parent reply other threads:[~2024-03-04 9:02 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <20240301101410.356007-1-kraxel@redhat.com>
2024-03-01 10:14 ` [PATCH 1/3] kvm: wire up KVM_CAP_VM_GPA_BITS for x86 Gerd Hoffmann
2024-03-01 16:13 ` Tao Su
2024-03-04 8:43 ` Gerd Hoffmann
2024-03-04 8:59 ` Tao Su [this message]
2024-03-04 11:47 ` Gerd Hoffmann
2024-03-04 15:15 ` Sean Christopherson
2024-03-05 2:59 ` Xiaoyao Li
2024-03-01 10:14 ` [PATCH 2/3] kvm/vmx: limit guest_phys_bits to 48 without 5-level ept Gerd Hoffmann
2024-03-01 10:14 ` [PATCH 3/3] kvm/svm: limit guest_phys_bits to 48 in 4-level paging mode Gerd Hoffmann
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