diff mbox series

[1/4] x86/sgx: Replace @is_secs_child with @pt in sgx_encl_ewb()

Message ID 20190823161616.27644-2-jarkko.sakkinen@linux.intel.com (mailing list archive)
State New, archived
Headers show
Series Remaining updates for v22 | expand

Commit Message

Jarkko Sakkinen Aug. 23, 2019, 4:16 p.m. UTC 
Sean complained about boolean parameters so I though that maybe it would
be good to rework the EWB flow in a way that it operates by a page type and
here is the result. The contract is and will be that as long as you give
the correct page type, you will get what you want. That is why I set
REG and TCS appropriately even though they are treated the same way
at this point of time.

Cc: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
---
 arch/x86/kernel/cpu/sgx/reclaim.c | 43 +++++++++++++++++++------------
 1 file changed, 27 insertions(+), 16 deletions(-)

Comments

Ayoun, Serge Aug. 26, 2019, 2:31 p.m. UTC | #1 
> On Behalf Of Jarkko Sakkinen
> Sent: Friday, August 23, 2019 19:16
> To: linux-sgx@vger.kernel.org
> Cc: Christopherson, Sean J <sean.j.christopherson@intel.com>; Ayoun,
> Serge <serge.ayoun@intel.com>; Katz-zamir, Shay <shay.katz-
> zamir@intel.com>; Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
> Subject: [PATCH 1/4] x86/sgx: Replace @is_secs_child with @pt in
> sgx_encl_ewb()
> 
> Sean complained about boolean parameters so I though that maybe it would
> be good to rework the EWB flow in a way that it operates by a page type and
> here is the result. The contract is and will be that as long as you give the
> correct page type, you will get what you want. That is why I set REG and TCS
> appropriately even though they are treated the same way at this point of
> time.
> 
> Cc: Sean Christopherson <sean.j.christopherson@intel.com>
> Signed-off-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
> ---
>  arch/x86/kernel/cpu/sgx/reclaim.c | 43 +++++++++++++++++++------------
>  1 file changed, 27 insertions(+), 16 deletions(-)
> 
> diff --git a/arch/x86/kernel/cpu/sgx/reclaim.c
> b/arch/x86/kernel/cpu/sgx/reclaim.c
> index 00f596c64a2d..3f10a8ff00b7 100644
> --- a/arch/x86/kernel/cpu/sgx/reclaim.c
> +++ b/arch/x86/kernel/cpu/sgx/reclaim.c
> @@ -221,7 +221,7 @@ static void sgx_reclaimer_block(struct sgx_epc_page
> *epc_page)
> 
>  static int __sgx_encl_ewb(struct sgx_encl *encl, struct sgx_epc_page
> *epc_page,
>  			  struct sgx_va_page *va_page, unsigned int
> va_offset,
> -			  bool is_secs_child)
> +			  unsigned int pt)
>  {
>  	struct sgx_encl_page *encl_page = epc_page->owner;
>  	struct sgx_pageinfo pginfo;
> @@ -232,10 +232,14 @@ static int __sgx_encl_ewb(struct sgx_encl *encl,
> struct sgx_epc_page *epc_page,
>  	struct page *pcmd;
>  	int ret;
> 
> -	if (is_secs_child)
> -		page_index = SGX_ENCL_PAGE_INDEX(encl_page);
> -	else
> +	if (pt != SGX_SECINFO_SECS && pt != SGX_SECINFO_TCS &&
> +	    pt != SGX_SECINFO_REG)
> +		return -EINVAL;

Not sure about this one since this 'if' should never happen, unless there is a bug
Not clear if the caller (sgx_encl_ewb) will handle -EINVAL properly.
Maybe would be better to issue some warning message or BUG_ON

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Jarkko Sakkinen Aug. 26, 2019, 4:25 p.m. UTC | #2 
On Mon, Aug 26, 2019 at 02:31:54PM +0000, Ayoun, Serge wrote:
> Not sure about this one since this 'if' should never happen, unless there is a bug
> Not clear if the caller (sgx_encl_ewb) will handle -EINVAL properly.
> Maybe would be better to issue some warning message or BUG_ON

The caller issues warning.

/Jarkko
diff mbox series

Patch

diff --git a/arch/x86/kernel/cpu/sgx/reclaim.c b/arch/x86/kernel/cpu/sgx/reclaim.c
index 00f596c64a2d..3f10a8ff00b7 100644
--- a/arch/x86/kernel/cpu/sgx/reclaim.c
+++ b/arch/x86/kernel/cpu/sgx/reclaim.c
@@ -221,7 +221,7 @@  static void sgx_reclaimer_block(struct sgx_epc_page *epc_page)
 
 static int __sgx_encl_ewb(struct sgx_encl *encl, struct sgx_epc_page *epc_page,
 			  struct sgx_va_page *va_page, unsigned int va_offset,
-			  bool is_secs_child)
+			  unsigned int pt)
 {
 	struct sgx_encl_page *encl_page = epc_page->owner;
 	struct sgx_pageinfo pginfo;
@@ -232,10 +232,14 @@  static int __sgx_encl_ewb(struct sgx_encl *encl, struct sgx_epc_page *epc_page,
 	struct page *pcmd;
 	int ret;
 
-	if (is_secs_child)
-		page_index = SGX_ENCL_PAGE_INDEX(encl_page);
-	else
+	if (pt != SGX_SECINFO_SECS && pt != SGX_SECINFO_TCS &&
+	    pt != SGX_SECINFO_REG)
+		return -EINVAL;
+
+	if (pt == SGX_SECINFO_SECS)
 		page_index = PFN_DOWN(encl->size);
+	else
+		page_index = SGX_ENCL_PAGE_INDEX(encl_page);
 
 	pcmd_index = sgx_pcmd_index(encl, page_index);
 	pcmd_offset = sgx_pcmd_offset(page_index);
@@ -300,7 +304,7 @@  static const cpumask_t *sgx_encl_ewb_cpumask(struct sgx_encl *encl)
 	return cpumask;
 }
 
-static void sgx_encl_ewb(struct sgx_epc_page *epc_page, bool is_secs_child)
+static void sgx_encl_ewb(struct sgx_epc_page *epc_page, unsigned int pt)
 {
 	struct sgx_encl_page *encl_page = epc_page->owner;
 	struct sgx_encl *encl = encl_page->encl;
@@ -317,8 +321,7 @@  static void sgx_encl_ewb(struct sgx_epc_page *epc_page, bool is_secs_child)
 		if (sgx_va_page_full(va_page))
 			list_move_tail(&va_page->list, &encl->va_pages);
 
-		ret = __sgx_encl_ewb(encl, epc_page, va_page, va_offset,
-				     is_secs_child);
+		ret = __sgx_encl_ewb(encl, epc_page, va_page, va_offset, pt);
 		if (ret == SGX_NOT_TRACKED) {
 			ret = __etrack(sgx_epc_addr(encl->secs.epc_page));
 			if (ret) {
@@ -327,8 +330,8 @@  static void sgx_encl_ewb(struct sgx_epc_page *epc_page, bool is_secs_child)
 					ENCLS_WARN(ret, "ETRACK");
 			}
 
-			ret = __sgx_encl_ewb(encl, epc_page, va_page,
-					     va_offset, is_secs_child);
+			ret = __sgx_encl_ewb(encl, epc_page, va_page, va_offset,
+					     pt);
 			if (ret == SGX_NOT_TRACKED) {
 				/*
 				 * Slow path, send IPIs to kick cpus out of the
@@ -340,7 +343,7 @@  static void sgx_encl_ewb(struct sgx_epc_page *epc_page, bool is_secs_child)
 				on_each_cpu_mask(sgx_encl_ewb_cpumask(encl),
 						 sgx_ipi_cb, NULL, 1);
 				ret = __sgx_encl_ewb(encl, epc_page, va_page,
-						     va_offset, is_secs_child);
+						     va_offset, pt);
 			}
 		}
 
@@ -350,12 +353,13 @@  static void sgx_encl_ewb(struct sgx_epc_page *epc_page, bool is_secs_child)
 
 		encl_page->desc |= va_offset;
 		encl_page->va_page = va_page;
-	} else if (is_secs_child) {
+	} else if (pt != SGX_SECINFO_SECS) {
 		ret = __eremove(sgx_epc_addr(epc_page));
 		WARN(ret, "EREMOVE returned %d\n", ret);
 	}
 
-	if (!is_secs_child)
+	/* The reclaimer is not aware of SECS pages. */
+	if (pt == SGX_SECINFO_SECS)
 		sgx_free_page(epc_page);
 
 	encl_page->epc_page = NULL;
@@ -365,15 +369,22 @@  static void sgx_reclaimer_write(struct sgx_epc_page *epc_page)
 {
 	struct sgx_encl_page *encl_page = epc_page->owner;
 	struct sgx_encl *encl = encl_page->encl;
+	unsigned int pt;
+
+	if (encl_page->desc & SGX_ENCL_PAGE_TCS)
+		pt = SGX_SECINFO_TCS;
+	else
+		pt = SGX_SECINFO_REG;
 
 	mutex_lock(&encl->lock);
 
-	sgx_encl_ewb(epc_page, true);
+	sgx_encl_ewb(epc_page, pt);
+
 	encl->secs_child_cnt--;
+
 	if (!encl->secs_child_cnt &&
-	    (encl->flags & (SGX_ENCL_DEAD | SGX_ENCL_INITIALIZED))) {
-		sgx_encl_ewb(encl->secs.epc_page, false);
-	}
+	    (encl->flags & (SGX_ENCL_DEAD | SGX_ENCL_INITIALIZED)))
+		sgx_encl_ewb(encl->secs.epc_page, SGX_SECINFO_SECS);
 
 	mutex_unlock(&encl->lock);
 }