x86/svm: Drop svm_vm{load,save}() helpers

[Xen-devel] [PATCH] x86/svm: Drop svm_vm{load,save}() helpers

Posted by Andrew Cooper 6 years, 7 months ago

Following on from c/s 7d161f6537 "x86/svm: Fix svm_vmcb_dump() when used in
current context", there is now only a single user of svm_vmsave() remaining in
the tree, with all users moved to svm_vm{load,save}_pa().

nv->nv_n1vmcx has a matching nv->nv_n1vmcx_pa which is always correct, and
avoids a redundant __pa() translation behind the scenes.

With this gone, all VM{LOAD,SAVE} operations are using paddr_t's which is more
efficient, so drop the svm_vm{load,save}() helpers to avoid uses of them
reappearing in the future.

Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
---
CC: Jan Beulich <JBeulich@suse.com>
CC: Wei Liu <wl@xen.org>
CC: Roger Pau Monné <roger.pau@citrix.com>
CC: Boris Ostrovsky <boris.ostrovsky@oracle.com>
CC: Suravee Suthikulpanit <suravee.suthikulpanit@amd.com>
CC: Brian Woods <brian.woods@amd.com>

It turns out I was mistaken about how complicated this was.
---
 xen/arch/x86/hvm/svm/nestedsvm.c  | 2 +-
 xen/include/asm-x86/hvm/svm/svm.h | 3 ---
 2 files changed, 1 insertion(+), 4 deletions(-)

diff --git a/xen/arch/x86/hvm/svm/nestedsvm.c b/xen/arch/x86/hvm/svm/nestedsvm.c
index 35c1a04..fef124f 100644
--- a/xen/arch/x86/hvm/svm/nestedsvm.c
+++ b/xen/arch/x86/hvm/svm/nestedsvm.c
@@ -1030,7 +1030,7 @@ nsvm_vmcb_prepare4vmexit(struct vcpu *v, struct cpu_user_regs *regs)
     struct vmcb_struct *ns_vmcb = nv->nv_vvmcx;
     struct vmcb_struct *n2vmcb = nv->nv_n2vmcx;
 
-    svm_vmsave(nv->nv_n1vmcx);
+    svm_vmsave_pa(nv->nv_n1vmcx_pa);
 
     /* Cache guest physical address of virtual vmcb
      * for VMCB Cleanbit emulation.
diff --git a/xen/include/asm-x86/hvm/svm/svm.h b/xen/include/asm-x86/hvm/svm/svm.h
index 6e688a8..16a994e 100644
--- a/xen/include/asm-x86/hvm/svm/svm.h
+++ b/xen/include/asm-x86/hvm/svm/svm.h
@@ -22,9 +22,6 @@
 
 #include <xen/types.h>
 
-#define svm_vmload(x)     svm_vmload_pa(__pa(x))
-#define svm_vmsave(x)     svm_vmsave_pa(__pa(x))
-
 static inline void svm_vmload_pa(paddr_t vmcb)
 {
     asm volatile (
-- 
2.1.4


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Re: [Xen-devel] [PATCH] x86/svm: Drop svm_vm{load,save}() helpers

Posted by Jan Beulich 6 years, 7 months ago

>>> On 20.06.19 at 14:06, <andrew.cooper3@citrix.com> wrote:
> Following on from c/s 7d161f6537 "x86/svm: Fix svm_vmcb_dump() when used in
> current context", there is now only a single user of svm_vmsave() remaining in
> the tree, with all users moved to svm_vm{load,save}_pa().
> 
> nv->nv_n1vmcx has a matching nv->nv_n1vmcx_pa which is always correct, and
> avoids a redundant __pa() translation behind the scenes.
> 
> With this gone, all VM{LOAD,SAVE} operations are using paddr_t's which is more
> efficient, so drop the svm_vm{load,save}() helpers to avoid uses of them
> reappearing in the future.
> 
> Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>

Reviewed-by: Jan Beulich <jbeulich@suse.com>

> It turns out I was mistaken about how complicated this was.

That was my hope, but it has been too long since I had last looked
at the nesting code in any level of detail.

> --- a/xen/include/asm-x86/hvm/svm/svm.h
> +++ b/xen/include/asm-x86/hvm/svm/svm.h
> @@ -22,9 +22,6 @@
>  
>  #include <xen/types.h>
>  
> -#define svm_vmload(x)     svm_vmload_pa(__pa(x))
> -#define svm_vmsave(x)     svm_vmsave_pa(__pa(x))
> -
>  static inline void svm_vmload_pa(paddr_t vmcb)

Down the road we may want to consider dropping the now
pointless _pa suffixes.

Jan



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Re: [Xen-devel] [PATCH] x86/svm: Drop svm_vm{load,save}() helpers

Posted by Woods, Brian 6 years, 7 months ago

On Thu, Jun 20, 2019 at 01:06:21PM +0100, Andy Cooper wrote:
> Following on from c/s 7d161f6537 "x86/svm: Fix svm_vmcb_dump() when used in
> current context", there is now only a single user of svm_vmsave() remaining in
> the tree, with all users moved to svm_vm{load,save}_pa().
> 
> nv->nv_n1vmcx has a matching nv->nv_n1vmcx_pa which is always correct, and
> avoids a redundant __pa() translation behind the scenes.
> 
> With this gone, all VM{LOAD,SAVE} operations are using paddr_t's which is more
> efficient, so drop the svm_vm{load,save}() helpers to avoid uses of them
> reappearing in the future.
> 
> Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>

Acked-by: Brian Woods <brian.woods@amd.com>

> ---
> CC: Jan Beulich <JBeulich@suse.com>
> CC: Wei Liu <wl@xen.org>
> CC: Roger Pau Monné <roger.pau@citrix.com>
> CC: Boris Ostrovsky <boris.ostrovsky@oracle.com>
> CC: Suravee Suthikulpanit <suravee.suthikulpanit@amd.com>
> CC: Brian Woods <brian.woods@amd.com>
> 
> It turns out I was mistaken about how complicated this was.
> ---
>  xen/arch/x86/hvm/svm/nestedsvm.c  | 2 +-
>  xen/include/asm-x86/hvm/svm/svm.h | 3 ---
>  2 files changed, 1 insertion(+), 4 deletions(-)
> 
> diff --git a/xen/arch/x86/hvm/svm/nestedsvm.c b/xen/arch/x86/hvm/svm/nestedsvm.c
> index 35c1a04..fef124f 100644
> --- a/xen/arch/x86/hvm/svm/nestedsvm.c
> +++ b/xen/arch/x86/hvm/svm/nestedsvm.c
> @@ -1030,7 +1030,7 @@ nsvm_vmcb_prepare4vmexit(struct vcpu *v, struct cpu_user_regs *regs)
>      struct vmcb_struct *ns_vmcb = nv->nv_vvmcx;
>      struct vmcb_struct *n2vmcb = nv->nv_n2vmcx;
>  
> -    svm_vmsave(nv->nv_n1vmcx);
> +    svm_vmsave_pa(nv->nv_n1vmcx_pa);
>  
>      /* Cache guest physical address of virtual vmcb
>       * for VMCB Cleanbit emulation.
> diff --git a/xen/include/asm-x86/hvm/svm/svm.h b/xen/include/asm-x86/hvm/svm/svm.h
> index 6e688a8..16a994e 100644
> --- a/xen/include/asm-x86/hvm/svm/svm.h
> +++ b/xen/include/asm-x86/hvm/svm/svm.h
> @@ -22,9 +22,6 @@
>  
>  #include <xen/types.h>
>  
> -#define svm_vmload(x)     svm_vmload_pa(__pa(x))
> -#define svm_vmsave(x)     svm_vmsave_pa(__pa(x))
> -
>  static inline void svm_vmload_pa(paddr_t vmcb)
>  {
>      asm volatile (
> -- 
> 2.1.4
> 

-- 
Brian Woods

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