KVM Archive on lore.kernel.org
 help / color / Atom feed
From: Maran Wilson <maran.wilson@oracle.com>
To: Liran Alon <liran.alon@oracle.com>, qemu-devel@nongnu.org
Cc: ehabkost@redhat.com, kvm@vger.kernel.org, mtosatti@redhat.com,
	dgilbert@redhat.com, pbonzini@redhat.com, rth@twiddle.net,
	jmattson@google.com
Subject: Re: [Qemu-devel] [QEMU PATCH v3 5/9] linux-headers: i386: Modify struct kvm_nested_state to have explicit fields for data
Date: Tue, 18 Jun 2019 15:16:15 -0700
Message-ID: <fad1387b-54fd-cbfc-89c8-433d9e8da141@oracle.com> (raw)
In-Reply-To: <20190617175658.135869-6-liran.alon@oracle.com>

On 6/17/2019 10:56 AM, Liran Alon wrote:
> Improve the KVM_{GET,SET}_NESTED_STATE structs by detailing the format
> of VMX nested state data in a struct.
>
> In order to avoid changing the ioctl values of
> KVM_{GET,SET}_NESTED_STATE, there is a need to preserve
> sizeof(struct kvm_nested_state). This is done by defining the data
> struct as "data.vmx[0]". It was the most elegant way I found to
> preserve struct size while still keeping struct readable and easy to
> maintain. It does have a misfortunate side-effect that now it has to be
> accessed as "data.vmx[0]" rather than just "data.vmx".
>
> Because we are already modifying these structs, I also modified the
> following:
> * Define the "format" field values as macros.
> * Rename vmcs_pa to vmcs12_pa for better readability.
> * Add stub structs for AMD SVM.
>
> Signed-off-by: Liran Alon <liran.alon@oracle.com>
> ---
>   linux-headers/asm-x86/kvm.h | 41 +++++++++++++++++++++++++++----------
>   1 file changed, 30 insertions(+), 11 deletions(-)
>
> diff --git a/linux-headers/asm-x86/kvm.h b/linux-headers/asm-x86/kvm.h
> index 7a0e64ccd6ff..e655d108af19 100644
> --- a/linux-headers/asm-x86/kvm.h
> +++ b/linux-headers/asm-x86/kvm.h
> @@ -383,6 +383,9 @@ struct kvm_sync_regs {
>   #define KVM_X86_QUIRK_LAPIC_MMIO_HOLE	(1 << 2)
>   #define KVM_X86_QUIRK_OUT_7E_INC_RIP	(1 << 3)
>   
> +#define KVM_STATE_NESTED_FORMAT_VMX	0
> +#define KVM_STATE_NESTED_FORMAT_SVM	1
> +
>   #define KVM_STATE_NESTED_GUEST_MODE	0x00000001
>   #define KVM_STATE_NESTED_RUN_PENDING	0x00000002
>   #define KVM_STATE_NESTED_EVMCS		0x00000004
> @@ -390,35 +393,51 @@ struct kvm_sync_regs {
>   #define KVM_STATE_NESTED_SMM_GUEST_MODE	0x00000001
>   #define KVM_STATE_NESTED_SMM_VMXON	0x00000002
>   
> -struct kvm_vmx_nested_state {
> +struct kvm_vmx_nested_state_data {
> +	__u8 vmcs12[0x1000];
> +	__u8 shadow_vmcs12[0x1000];

I assume you will replace this magic 0x1000 value too, as discussed with 
respect to patch 7?

Thanks,
-Maran

> +};
> +
> +struct kvm_vmx_nested_state_hdr {
>   	__u64 vmxon_pa;
> -	__u64 vmcs_pa;
> +	__u64 vmcs12_pa;
>   
>   	struct {
>   		__u16 flags;
>   	} smm;
>   };
>   
> +struct kvm_svm_nested_state_data {
> +	/* TODO: Implement */
> +};
> +
> +struct kvm_svm_nested_state_hdr {
> +	/* TODO: Implement */
> +};
> +
>   /* for KVM_CAP_NESTED_STATE */
>   struct kvm_nested_state {
> -	/* KVM_STATE_* flags */
>   	__u16 flags;
> -
> -	/* 0 for VMX, 1 for SVM.  */
>   	__u16 format;
> -
> -	/* 128 for SVM, 128 + VMCS size for VMX.  */
>   	__u32 size;
>   
>   	union {
> -		/* VMXON, VMCS */
> -		struct kvm_vmx_nested_state vmx;
> +		struct kvm_vmx_nested_state_hdr vmx;
> +		struct kvm_svm_nested_state_hdr svm;
>   
>   		/* Pad the header to 128 bytes.  */
>   		__u8 pad[120];
> -	};
> +	} hdr;
>   
> -	__u8 data[0];
> +	/*
> +	 * Define data region as 0 bytes to preserve backwards-compatability
> +	 * to old definition of kvm_nested_state in order to avoid changing
> +	 * KVM_{GET,PUT}_NESTED_STATE ioctl values.
> +	 */
> +	union {
> +		struct kvm_vmx_nested_state_data vmx[0];
> +		struct kvm_svm_nested_state_data svm[0];
> +	} data;
>   };
>   
>   #endif /* _ASM_X86_KVM_H */


  reply index

Thread overview: 27+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-06-17 17:56 [QEMU PATCH v3 0/9]: KVM: i386: Add support for save and restore of nested state Liran Alon
2019-06-17 17:56 ` [QEMU PATCH v3 1/9] KVM: Introduce kvm_arch_destroy_vcpu() Liran Alon
2019-06-18 22:15   ` [Qemu-devel] " Maran Wilson
2019-06-17 17:56 ` [QEMU PATCH v3 2/9] KVM: i386: Use symbolic constant for #DB/#BP exception constants Liran Alon
2019-06-17 17:56 ` [QEMU PATCH v3 3/9] KVM: i386: Re-inject #DB to guest with updated DR6 Liran Alon
2019-06-17 17:56 ` [QEMU PATCH v3 4/9] KVM: i386: Block migration for vCPUs exposed with nested virtualization Liran Alon
2019-06-18  8:44   ` Dr. David Alan Gilbert
2019-06-18 22:16   ` [Qemu-devel] " Maran Wilson
2019-06-17 17:56 ` [QEMU PATCH v3 5/9] linux-headers: i386: Modify struct kvm_nested_state to have explicit fields for data Liran Alon
2019-06-18 22:16   ` Maran Wilson [this message]
2019-06-17 17:56 ` [QEMU PATCH v3 6/9] vmstate: Add support for kernel integer types Liran Alon
2019-06-18  8:55   ` Dr. David Alan Gilbert
2019-06-18 15:36     ` Liran Alon
2019-06-18 15:42       ` Dr. David Alan Gilbert
2019-06-18 16:44         ` Paolo Bonzini
2019-06-17 17:56 ` [QEMU PATCH v3 7/9] KVM: i386: Add support for save and restore nested state Liran Alon
2019-06-18  9:03   ` Dr. David Alan Gilbert
2019-06-18 15:40     ` Liran Alon
2019-06-18 15:48       ` Dr. David Alan Gilbert
2019-06-18 15:50         ` Liran Alon
2019-06-18 16:16         ` Paolo Bonzini
2019-06-18 22:16   ` [Qemu-devel] " Maran Wilson
2019-06-17 17:56 ` [QEMU PATCH v3 8/9] KVM: i386: Add support for KVM_CAP_EXCEPTION_PAYLOAD Liran Alon
2019-06-18  9:07   ` Dr. David Alan Gilbert
2019-06-18 15:45     ` Liran Alon
2019-06-17 17:56 ` [QEMU PATCH v3 9/9] KVM: i386: Remove VMX migration blocker Liran Alon
2019-06-18 22:17   ` [Qemu-devel] " Maran Wilson

Reply instructions:

You may reply publically 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=fad1387b-54fd-cbfc-89c8-433d9e8da141@oracle.com \
    --to=maran.wilson@oracle.com \
    --cc=dgilbert@redhat.com \
    --cc=ehabkost@redhat.com \
    --cc=jmattson@google.com \
    --cc=kvm@vger.kernel.org \
    --cc=liran.alon@oracle.com \
    --cc=mtosatti@redhat.com \
    --cc=pbonzini@redhat.com \
    --cc=qemu-devel@nongnu.org \
    --cc=rth@twiddle.net \
    /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

KVM Archive on lore.kernel.org

Archives are clonable:
	git clone --mirror https://lore.kernel.org/kvm/0 kvm/git/0.git

	# If you have public-inbox 1.1+ installed, you may
	# initialize and index your mirror using the following commands:
	public-inbox-init -V2 kvm kvm/ https://lore.kernel.org/kvm \
		kvm@vger.kernel.org
	public-inbox-index kvm

Example config snippet for mirrors

Newsgroup available over NNTP:
	nntp://nntp.lore.kernel.org/org.kernel.vger.kvm


AGPL code for this site: git clone https://public-inbox.org/public-inbox.git