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From: kernel test robot <lkp@intel.com>
To: kbuild@lists.01.org
Subject: Re: [PATCH v3 02/12] KVM: x86: Introduce allow list for MSR emulation
Date: Thu, 27 Aug 2020 22:06:58 +0800	[thread overview]
Message-ID: <202008272243.korwThnS%lkp@intel.com> (raw)

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CC: kbuild-all(a)lists.01.org
In-Reply-To: <20200818211533.849501-3-aaronlewis@google.com>
References: <20200818211533.849501-3-aaronlewis@google.com>
TO: Aaron Lewis <aaronlewis@google.com>
TO: jmattson(a)google.com
TO: graf(a)amazon.com
CC: pshier(a)google.com
CC: oupton(a)google.com
CC: kvm(a)vger.kernel.org
CC: Aaron Lewis <aaronlewis@google.com>
CC: KarimAllah Ahmed <karahmed@amazon.de>

Hi Aaron,

Thank you for the patch! Perhaps something to improve:

[auto build test WARNING on kvm/linux-next]
[also build test WARNING on v5.9-rc2 next-20200827]
[cannot apply to kvms390/next vhost/linux-next]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch]

url:    https://github.com/0day-ci/linux/commits/Aaron-Lewis/Allow-userspace-to-manage-MSRs/20200819-051903
base:   https://git.kernel.org/pub/scm/virt/kvm/kvm.git linux-next
:::::: branch date: 9 days ago
:::::: commit date: 9 days ago
config: x86_64-randconfig-m001-20200827 (attached as .config)
compiler: gcc-9 (Debian 9.3.0-15) 9.3.0

If you fix the issue, kindly add following tag as appropriate
Reported-by: kernel test robot <lkp@intel.com>
Reported-by: Dan Carpenter <dan.carpenter@oracle.com>

smatch warnings:
arch/x86/kvm/x86.c:5248 kvm_vm_ioctl_add_msr_allowlist() error: 'bitmap' dereferencing possible ERR_PTR()

# https://github.com/0day-ci/linux/commit/107c87325cf461b7b1bd07bb6ddbaf808a8d8a2a
git remote add linux-review https://github.com/0day-ci/linux
git fetch --no-tags linux-review Aaron-Lewis/Allow-userspace-to-manage-MSRs/20200819-051903
git checkout 107c87325cf461b7b1bd07bb6ddbaf808a8d8a2a
vim +/bitmap +5248 arch/x86/kvm/x86.c

107c87325cf461 Aaron Lewis 2020-08-18  5180  
107c87325cf461 Aaron Lewis 2020-08-18  5181  static int kvm_vm_ioctl_add_msr_allowlist(struct kvm *kvm, void __user *argp)
107c87325cf461 Aaron Lewis 2020-08-18  5182  {
107c87325cf461 Aaron Lewis 2020-08-18  5183  	struct msr_bitmap_range *ranges = kvm->arch.msr_allowlist_ranges;
107c87325cf461 Aaron Lewis 2020-08-18  5184  	struct kvm_msr_allowlist __user *user_msr_allowlist = argp;
107c87325cf461 Aaron Lewis 2020-08-18  5185  	struct msr_bitmap_range range;
107c87325cf461 Aaron Lewis 2020-08-18  5186  	struct kvm_msr_allowlist kernel_msr_allowlist;
107c87325cf461 Aaron Lewis 2020-08-18  5187  	unsigned long *bitmap = NULL;
107c87325cf461 Aaron Lewis 2020-08-18  5188  	size_t bitmap_size;
107c87325cf461 Aaron Lewis 2020-08-18  5189  	int r = 0;
107c87325cf461 Aaron Lewis 2020-08-18  5190  
107c87325cf461 Aaron Lewis 2020-08-18  5191  	if (copy_from_user(&kernel_msr_allowlist, user_msr_allowlist,
107c87325cf461 Aaron Lewis 2020-08-18  5192  			   sizeof(kernel_msr_allowlist))) {
107c87325cf461 Aaron Lewis 2020-08-18  5193  		r = -EFAULT;
107c87325cf461 Aaron Lewis 2020-08-18  5194  		goto out;
107c87325cf461 Aaron Lewis 2020-08-18  5195  	}
107c87325cf461 Aaron Lewis 2020-08-18  5196  
107c87325cf461 Aaron Lewis 2020-08-18  5197  	bitmap_size = BITS_TO_LONGS(kernel_msr_allowlist.nmsrs) * sizeof(long);
107c87325cf461 Aaron Lewis 2020-08-18  5198  	if (bitmap_size > KVM_MSR_ALLOWLIST_MAX_LEN) {
107c87325cf461 Aaron Lewis 2020-08-18  5199  		r = -EINVAL;
107c87325cf461 Aaron Lewis 2020-08-18  5200  		goto out;
107c87325cf461 Aaron Lewis 2020-08-18  5201  	}
107c87325cf461 Aaron Lewis 2020-08-18  5202  
107c87325cf461 Aaron Lewis 2020-08-18  5203  	bitmap = memdup_user(user_msr_allowlist->bitmap, bitmap_size);
107c87325cf461 Aaron Lewis 2020-08-18  5204  	if (IS_ERR(bitmap)) {
107c87325cf461 Aaron Lewis 2020-08-18  5205  		r = PTR_ERR(bitmap);
107c87325cf461 Aaron Lewis 2020-08-18  5206  		goto out;
107c87325cf461 Aaron Lewis 2020-08-18  5207  	}
107c87325cf461 Aaron Lewis 2020-08-18  5208  
107c87325cf461 Aaron Lewis 2020-08-18  5209  	range = (struct msr_bitmap_range) {
107c87325cf461 Aaron Lewis 2020-08-18  5210  		.flags = kernel_msr_allowlist.flags,
107c87325cf461 Aaron Lewis 2020-08-18  5211  		.base = kernel_msr_allowlist.base,
107c87325cf461 Aaron Lewis 2020-08-18  5212  		.nmsrs = kernel_msr_allowlist.nmsrs,
107c87325cf461 Aaron Lewis 2020-08-18  5213  		.bitmap = bitmap,
107c87325cf461 Aaron Lewis 2020-08-18  5214  	};
107c87325cf461 Aaron Lewis 2020-08-18  5215  
107c87325cf461 Aaron Lewis 2020-08-18  5216  	if (range.flags & ~(KVM_MSR_ALLOW_READ | KVM_MSR_ALLOW_WRITE)) {
107c87325cf461 Aaron Lewis 2020-08-18  5217  		r = -EINVAL;
107c87325cf461 Aaron Lewis 2020-08-18  5218  		goto out;
107c87325cf461 Aaron Lewis 2020-08-18  5219  	}
107c87325cf461 Aaron Lewis 2020-08-18  5220  
107c87325cf461 Aaron Lewis 2020-08-18  5221  	/*
107c87325cf461 Aaron Lewis 2020-08-18  5222  	 * Protect from concurrent calls to this function that could trigger
107c87325cf461 Aaron Lewis 2020-08-18  5223  	 * a TOCTOU violation on kvm->arch.msr_allowlist_ranges_count.
107c87325cf461 Aaron Lewis 2020-08-18  5224  	 */
107c87325cf461 Aaron Lewis 2020-08-18  5225  	mutex_lock(&kvm->lock);
107c87325cf461 Aaron Lewis 2020-08-18  5226  
107c87325cf461 Aaron Lewis 2020-08-18  5227  	if (kvm->arch.msr_allowlist_ranges_count >=
107c87325cf461 Aaron Lewis 2020-08-18  5228  	    ARRAY_SIZE(kvm->arch.msr_allowlist_ranges)) {
107c87325cf461 Aaron Lewis 2020-08-18  5229  		r = -E2BIG;
107c87325cf461 Aaron Lewis 2020-08-18  5230  		goto out_locked;
107c87325cf461 Aaron Lewis 2020-08-18  5231  	}
107c87325cf461 Aaron Lewis 2020-08-18  5232  
107c87325cf461 Aaron Lewis 2020-08-18  5233  	if (msr_range_overlaps(kvm, &range)) {
107c87325cf461 Aaron Lewis 2020-08-18  5234  		r = -EINVAL;
107c87325cf461 Aaron Lewis 2020-08-18  5235  		goto out_locked;
107c87325cf461 Aaron Lewis 2020-08-18  5236  	}
107c87325cf461 Aaron Lewis 2020-08-18  5237  
107c87325cf461 Aaron Lewis 2020-08-18  5238  	/* Everything ok, add this range identifier to our global pool */
107c87325cf461 Aaron Lewis 2020-08-18  5239  	ranges[kvm->arch.msr_allowlist_ranges_count] = range;
107c87325cf461 Aaron Lewis 2020-08-18  5240  	/* Make sure we filled the array before we tell anyone to walk it */
107c87325cf461 Aaron Lewis 2020-08-18  5241  	smp_wmb();
107c87325cf461 Aaron Lewis 2020-08-18  5242  	kvm->arch.msr_allowlist_ranges_count++;
107c87325cf461 Aaron Lewis 2020-08-18  5243  
107c87325cf461 Aaron Lewis 2020-08-18  5244  out_locked:
107c87325cf461 Aaron Lewis 2020-08-18  5245  	mutex_unlock(&kvm->lock);
107c87325cf461 Aaron Lewis 2020-08-18  5246  out:
107c87325cf461 Aaron Lewis 2020-08-18  5247  	if (r)
107c87325cf461 Aaron Lewis 2020-08-18 @5248  		kfree(bitmap);
107c87325cf461 Aaron Lewis 2020-08-18  5249  
107c87325cf461 Aaron Lewis 2020-08-18  5250  	return r;
107c87325cf461 Aaron Lewis 2020-08-18  5251  }
107c87325cf461 Aaron Lewis 2020-08-18  5252  

---
0-DAY CI Kernel Test Service, Intel Corporation
https://lists.01.org/hyperkitty/list/kbuild-all(a)lists.01.org

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             reply	other threads:[~2020-08-27 14:06 UTC|newest]

Thread overview: 10+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-08-27 14:06 kernel test robot [this message]
  -- strict thread matches above, loose matches on Subject: below --
2020-08-18 21:15 [PATCH v3 00/12] Allow userspace to manage MSRs Aaron Lewis
2020-08-18 21:15 ` [PATCH v3 02/12] KVM: x86: Introduce allow list for MSR emulation Aaron Lewis
2020-08-19  8:53   ` Alexander Graf
2020-08-31 10:39   ` Dan Carpenter
2020-08-31 10:39     ` Dan Carpenter
2020-08-31 10:39     ` Dan Carpenter
2020-09-01 19:13     ` Alexander Graf
2020-09-02  7:31       ` Dan Carpenter
2020-09-02  7:31         ` Dan Carpenter
2020-09-02  7:31         ` Dan Carpenter

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