Commit d5394c05 authored by Anshuman Khandual's avatar Anshuman Khandual Committed by Michael Ellerman
Browse files

powerpc/pseries/svm: Use shared memory for Debug Trace Log (DTL) 



Secure guests need to share the DTL buffers with the hypervisor. To that
end, use a kmem_cache constructor which converts the underlying buddy
allocated SLUB cache pages into shared memory.

Signed-off-by: default avatarAnshuman Khandual <khandual@linux.vnet.ibm.com>
Signed-off-by: default avatarThiago Jung Bauermann <bauerman@linux.ibm.com>
Signed-off-by: default avatarMichael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20190820021326.6884-10-bauerman@linux.ibm.com
parent bd104e6d

arch/powerpc/include/asm/svm.h

+5 −0
Original line number Diff line number Diff line
@@ -15,6 +15,9 @@ static inline bool is_secure_guest(void) 
	return mfmsr() & MSR_S;

}



void dtl_cache_ctor(void *addr);

#define get_dtl_cache_ctor()	(is_secure_guest() ? dtl_cache_ctor : NULL)



#else /* CONFIG_PPC_SVM */



static inline bool is_secure_guest(void)
@@ -22,5 +25,7 @@ static inline bool is_secure_guest(void) 
	return false;

}



#define get_dtl_cache_ctor() NULL



#endif /* CONFIG_PPC_SVM */

#endif /* _ASM_POWERPC_SVM_H */

arch/powerpc/platforms/pseries/Makefile

+1 −0
Original line number Diff line number Diff line
@@ -26,6 +26,7 @@ obj-$(CONFIG_IBMVIO) += vio.o 
obj-$(CONFIG_IBMEBUS)		+= ibmebus.o

obj-$(CONFIG_PAPR_SCM)		+= papr_scm.o

obj-$(CONFIG_PPC_SPLPAR)	+= vphn.o

obj-$(CONFIG_PPC_SVM)		+= svm.o



ifdef CONFIG_PPC_PSERIES

obj-$(CONFIG_SUSPEND)		+= suspend.o

arch/powerpc/platforms/pseries/setup.c

+4 −1
Original line number Diff line number Diff line
@@ -69,6 +69,7 @@ 
#include <asm/security_features.h>

#include <asm/asm-const.h>

#include <asm/swiotlb.h>

#include <asm/svm.h>



#include "pseries.h"

#include "../../../../drivers/pci/pci.h"
@@ -297,8 +298,10 @@ static inline int alloc_dispatch_logs(void) 


static int alloc_dispatch_log_kmem_cache(void)

{

	void (*ctor)(void *) = get_dtl_cache_ctor();



	dtl_cache = kmem_cache_create("dtl", DISPATCH_LOG_BYTES,

						DISPATCH_LOG_BYTES, 0, NULL);

						DISPATCH_LOG_BYTES, 0, ctor);

	if (!dtl_cache) {

		pr_warn("Failed to create dispatch trace log buffer cache\n");

		pr_warn("Stolen time statistics will be unreliable\n");

arch/powerpc/platforms/pseries/svm.c

0 → 100644
+40 −0
Original line number Diff line number Diff line 
// SPDX-License-Identifier: GPL-2.0+

/*

 * Secure VM platform

 *

 * Copyright 2018 IBM Corporation

 * Author: Anshuman Khandual <khandual@linux.vnet.ibm.com>

 */



#include <linux/mm.h>

#include <asm/ultravisor.h>



/* There's one dispatch log per CPU. */

#define NR_DTL_PAGE (DISPATCH_LOG_BYTES * CONFIG_NR_CPUS / PAGE_SIZE)



static struct page *dtl_page_store[NR_DTL_PAGE];

static long dtl_nr_pages;



static bool is_dtl_page_shared(struct page *page)

{

	long i;



	for (i = 0; i < dtl_nr_pages; i++)

		if (dtl_page_store[i] == page)

			return true;



	return false;

}



void dtl_cache_ctor(void *addr)

{

	unsigned long pfn = PHYS_PFN(__pa(addr));

	struct page *page = pfn_to_page(pfn);



	if (!is_dtl_page_shared(page)) {

		dtl_page_store[dtl_nr_pages] = page;

		dtl_nr_pages++;

		WARN_ON(dtl_nr_pages >= NR_DTL_PAGE);

		uv_share_page(pfn, 1);

	}

}