All of lore.kernel.org
 help / color / mirror / Atom feed
From: Sean Christopherson <seanjc@google.com>
To: Sean Christopherson <seanjc@google.com>,
	Paolo Bonzini <pbonzini@redhat.com>
Cc: kvm@vger.kernel.org, linux-kernel@vger.kernel.org,
	Like Xu <like.xu.linux@gmail.com>, Like Xu <likexu@tencent.com>,
	Jim Mattson <jmattson@google.com>,
	Sandipan Das <sandipan.das@amd.com>
Subject: [PATCH v7 03/12] KVM: x86/pmu: Reject userspace attempts to set reserved GLOBAL_STATUS bits
Date: Fri,  2 Jun 2023 18:10:49 -0700	[thread overview]
Message-ID: <20230603011058.1038821-4-seanjc@google.com> (raw)
In-Reply-To: <20230603011058.1038821-1-seanjc@google.com>

From: Like Xu <likexu@tencent.com>

Reject userspace writes to MSR_CORE_PERF_GLOBAL_STATUS that attempt to set
reserved bits.  Allowing userspace to stuff reserved bits doesn't harm KVM
itself, but it's architecturally wrong and the guest can't clear the
unsupported bits, e.g. makes the guest's PMI handler very confused.

Signed-off-by: Like Xu <likexu@tencent.com>
[sean: rewrite changelog to avoid use of #GP, rebase on name change]
Signed-off-by: Sean Christopherson <seanjc@google.com>
---
 arch/x86/kvm/vmx/pmu_intel.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/arch/x86/kvm/vmx/pmu_intel.c b/arch/x86/kvm/vmx/pmu_intel.c
index edcf8670eb4e..efd113f24c1b 100644
--- a/arch/x86/kvm/vmx/pmu_intel.c
+++ b/arch/x86/kvm/vmx/pmu_intel.c
@@ -402,6 +402,9 @@ static int intel_pmu_set_msr(struct kvm_vcpu *vcpu, struct msr_data *msr_info)
 		if (!msr_info->host_initiated)
 			return 1; /* RO MSR */
 
+		if (data & pmu->global_status_mask)
+			return 1;
+
 		pmu->global_status = data;
 		break;
 	case MSR_CORE_PERF_GLOBAL_CTRL:
-- 
2.41.0.rc2.161.g9c6817b8e7-goog


  parent reply	other threads:[~2023-06-03  1:11 UTC|newest]

Thread overview: 14+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-06-03  1:10 [PATCH v7 00/12] KVM: x86: Add AMD Guest PerfMonV2 PMU support Sean Christopherson
2023-06-03  1:10 ` [PATCH v7 01/12] KVM: x86/pmu: Rename global_ovf_ctrl_mask to global_status_mask Sean Christopherson
2023-06-03  1:10 ` [PATCH v7 02/12] KVM: x86/pmu: Move reprogram_counters() to pmu.h Sean Christopherson
2023-06-03  1:10 ` Sean Christopherson [this message]
2023-06-03  1:10 ` [PATCH v7 04/12] KVM: x86/pmu: Move handling PERF_GLOBAL_CTRL and friends to common x86 Sean Christopherson
2023-06-03  1:10 ` [PATCH v7 05/12] KVM: x86/pmu: Provide Intel PMU's pmc_is_enabled() as generic x86 code Sean Christopherson
2023-06-03  1:10 ` [PATCH v7 06/12] KVM: x86: Explicitly zero cpuid "0xa" leaf when PMU is disabled Sean Christopherson
2023-06-03  1:10 ` [PATCH v7 07/12] KVM: x86/pmu: Disable vPMU if the minimum num of counters isn't met Sean Christopherson
2023-06-03  1:10 ` [PATCH v7 08/12] KVM: x86/pmu: Advertise PERFCTR_CORE iff the min nr of counters is met Sean Christopherson
2023-06-03  1:10 ` [PATCH v7 09/12] KVM: x86/pmu: Constrain the num of guest counters with kvm_pmu_cap Sean Christopherson
2023-06-03  1:10 ` [PATCH v7 10/12] KVM: x86/cpuid: Add a KVM-only leaf to redirect AMD PerfMonV2 flag Sean Christopherson
2023-06-03  1:10 ` [PATCH v7 11/12] KVM: x86/svm/pmu: Add AMD PerfMonV2 support Sean Christopherson
2023-06-03  1:10 ` [PATCH v7 12/12] KVM: x86/cpuid: Add AMD CPUID ExtPerfMonAndDbg leaf 0x80000022 Sean Christopherson
2023-06-07  0:55 ` [PATCH v7 00/12] KVM: x86: Add AMD Guest PerfMonV2 PMU support Sean Christopherson

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=20230603011058.1038821-4-seanjc@google.com \
    --to=seanjc@google.com \
    --cc=jmattson@google.com \
    --cc=kvm@vger.kernel.org \
    --cc=like.xu.linux@gmail.com \
    --cc=likexu@tencent.com \
    --cc=linux-kernel@vger.kernel.org \
    --cc=pbonzini@redhat.com \
    --cc=sandipan.das@amd.com \
    /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 an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.