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Date: Wed, 6 Mar 2024 16:43:51 -0800
From: David Matlack <dmatlack@google.com>
To: isaku.yamahata@intel.com
Cc: kvm@vger.kernel.org, isaku.yamahata@gmail.com,
	linux-kernel@vger.kernel.org,
	Sean Christopherson <seanjc@google.com>,
	Paolo Bonzini <pbonzini@redhat.com>,
	Michael Roth <michael.roth@amd.com>,
	Federico Parola <federico.parola@polito.it>
Subject: Re: [RFC PATCH 1/8] KVM: Document KVM_MAP_MEMORY ioctl
Message-ID: <ZekNx-WkGNrVfFRD@google.com>
References: <cover.1709288671.git.isaku.yamahata@intel.com>
 <c50dc98effcba3ff68a033661b2941b777c4fb5c.1709288671.git.isaku.yamahata@intel.com>
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On 2024-03-01 09:28 AM, isaku.yamahata@intel.com wrote:
> From: Isaku Yamahata <isaku.yamahata@intel.com>
> +
> +  struct kvm_memory_mapping {
> +	__u64 base_gfn;
> +	__u64 nr_pages;
> +	__u64 flags;
> +	__u64 source;
> +  };
> +
> +  /* For kvm_memory_mapping:: flags */
> +  #define KVM_MEMORY_MAPPING_FLAG_WRITE         _BITULL(0)
> +  #define KVM_MEMORY_MAPPING_FLAG_EXEC          _BITULL(1)
> +  #define KVM_MEMORY_MAPPING_FLAG_USER          _BITULL(2)
> +  #define KVM_MEMORY_MAPPING_FLAG_PRIVATE       _BITULL(3)
> +
> +KVM_MAP_MEMORY populates guest memory in the underlying mapping. If source is
> +not zero and it's supported (depending on underlying technology), the guest
> +memory content is populated with the source.

What does "populated with the source" mean?

> The flags field supports three
> +flags: KVM_MEMORY_MAPPING_FLAG_WRITE, KVM_MEMORY_MAPPING_FLAG_EXEC, and
> +KVM_MEMORY_MAPPING_FLAG_USER.

There are 4 flags.