linux-kernel - Re: [PATCH v7 3/5] x86/mm: Make tdx_enc_status

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Date:   Thu, 26 May 2022 11:38:25 -0300
From:   Wander Lairson Costa <wander@...hat.com>
To:     Kuppuswamy Sathyanarayanan 
        <sathyanarayanan.kuppuswamy@...ux.intel.com>
Cc:     Thomas Gleixner <tglx@...utronix.de>,
        Ingo Molnar <mingo@...hat.com>, Borislav Petkov <bp@...en8.de>,
        Dave Hansen <dave.hansen@...ux.intel.com>, x86@...nel.org,
        "H . Peter Anvin" <hpa@...or.com>,
        "Kirill A . Shutemov" <kirill.shutemov@...ux.intel.com>,
        Tony Luck <tony.luck@...el.com>,
        Andi Kleen <ak@...ux.intel.com>,
        Kai Huang <kai.huang@...el.com>,
        Isaku Yamahata <isaku.yamahata@...il.com>,
        marcelo.cerri@...onical.com, tim.gardner@...onical.com,
        khalid.elmously@...onical.com, philip.cox@...onical.com,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH v7 3/5] x86/mm: Make tdx_enc_status_changed() vmalloc
 address compatible

On Mon, May 23, 2022 at 09:05:15PM -0700, Kuppuswamy Sathyanarayanan wrote:
> set_memory_*crypted() APIs are used to change encryption or decryption
> page attributes for the given address. It also by default support the
> conversion for the vmalloc'ed memory address.
> 
> In TDX Guest, tdx_enc_status_changed() function is triggered by
> set_memory_*crypted() APIs when converting memory from/to shared or
> private. Internally this function uses __pa() for physical address
> conversion, which breaks the vmalloc address compatibility of the
> set_memory_*crypted() APIs.
> 
> So add support to fix the vmalloc'ed address compatibility issue.
> 
> Signed-off-by: Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@...ux.intel.com>
> ---
>  arch/x86/coco/tdx/tdx.c | 11 +++++++++--
>  1 file changed, 9 insertions(+), 2 deletions(-)
> 
> diff --git a/arch/x86/coco/tdx/tdx.c b/arch/x86/coco/tdx/tdx.c
> index b49211994864..37d58675ccf1 100644
> --- a/arch/x86/coco/tdx/tdx.c
> +++ b/arch/x86/coco/tdx/tdx.c
> @@ -15,6 +15,7 @@
>  #include <asm/idtentry.h>
>  #include <asm/irq_regs.h>
>  #include <asm/desc.h>
> +#include <asm/io.h>
>  
>  /* TDX module Call Leaf IDs */
>  #define TDX_GET_INFO			1
> @@ -680,8 +681,14 @@ static bool try_accept_one(phys_addr_t *start, unsigned long len,
>   */
>  static bool tdx_enc_status_changed(unsigned long vaddr, int numpages, bool enc)
>  {
> -	phys_addr_t start = __pa(vaddr);
> -	phys_addr_t end   = __pa(vaddr + numpages * PAGE_SIZE);
> +	phys_addr_t start, end;
> +
> +	if (is_vmalloc_addr((void *)vaddr))
> +		start = vmalloc_to_pfn((void *) vaddr) << PAGE_SHIFT;
> +	else
> +		start = __pa(vaddr);
> +
> +	end = start + numpages * PAGE_SIZE;
>  
>  	if (!enc) {
>  		/* Set the shared (decrypted) bits: */
> -- 
> 2.25.1
> 
> 

Acked-by: Wander Lairson Costa <wander@...hat.com>