Commit 24512afa authored by Brijesh Singh's avatar Brijesh Singh Committed by Borislav Petkov (AMD)
Browse files

crypto: ccp: Handle the legacy TMR allocation when SNP is enabled 



The behavior and requirement for the SEV-legacy command is altered when
the SNP firmware is in the INIT state. See SEV-SNP firmware ABI
specification for more details.

Allocate the Trusted Memory Region (TMR) as a 2MB-sized/aligned region
when SNP is enabled to satisfy new requirements for SNP. Continue
allocating a 1MB-sized region for !SNP configuration.

  [ bp: Carve out TMR allocation into a helper. ]

Signed-off-by: default avatarBrijesh Singh <brijesh.singh@amd.com>
Co-developed-by: default avatarAshish Kalra <ashish.kalra@amd.com>
Signed-off-by: default avatarAshish Kalra <ashish.kalra@amd.com>
Signed-off-by: default avatarMichael Roth <michael.roth@amd.com>
Signed-off-by: default avatarBorislav Petkov (AMD) <bp@alien8.de>
Link: https://lore.kernel.org/r/20240126041126.1927228-17-michael.roth@amd.com
parent 8dac6429

drivers/crypto/ccp/sev-dev.c

+167 −26
Original line number Diff line number Diff line
@@ -30,6 +30,7 @@ 
#include <asm/smp.h>

#include <asm/cacheflush.h>

#include <asm/e820/types.h>

#include <asm/sev.h>



#include "psp-dev.h"

#include "sev-dev.h"
@@ -73,9 +74,14 @@ static int psp_timeout; 
 *   The TMR is a 1MB area that must be 1MB aligned.  Use the page allocator

 *   to allocate the memory, which will return aligned memory for the specified

 *   allocation order.

 *

 * When SEV-SNP is enabled the TMR needs to be 2MB aligned and 2MB sized.

 */

#define SEV_ES_TMR_SIZE		(1024 * 1024)

#define SEV_TMR_SIZE		(1024 * 1024)

#define SNP_TMR_SIZE		(2 * 1024 * 1024)



static void *sev_es_tmr;

static size_t sev_es_tmr_size = SEV_TMR_SIZE;



/* INIT_EX NV Storage:

 *   The NV Storage is a 32Kb area and must be 4Kb page aligned.  Use the page
@@ -192,17 +198,6 @@ static int sev_cmd_buffer_len(int cmd) 
	return 0;

}



static void *sev_fw_alloc(unsigned long len)

{

	struct page *page;



	page = alloc_pages(GFP_KERNEL, get_order(len));

	if (!page)

		return NULL;



	return page_address(page);

}



static struct file *open_file_as_root(const char *filename, int flags, umode_t mode)

{

	struct file *fp;
@@ -333,6 +328,142 @@ static int sev_write_init_ex_file_if_required(int cmd_id) 
	return sev_write_init_ex_file();

}



/*

 * snp_reclaim_pages() needs __sev_do_cmd_locked(), and __sev_do_cmd_locked()

 * needs snp_reclaim_pages(), so a forward declaration is needed.

 */

static int __sev_do_cmd_locked(int cmd, void *data, int *psp_ret);



static int snp_reclaim_pages(unsigned long paddr, unsigned int npages, bool locked)

{

	int ret, err, i;



	paddr = __sme_clr(ALIGN_DOWN(paddr, PAGE_SIZE));



	for (i = 0; i < npages; i++, paddr += PAGE_SIZE) {

		struct sev_data_snp_page_reclaim data = {0};



		data.paddr = paddr;



		if (locked)

			ret = __sev_do_cmd_locked(SEV_CMD_SNP_PAGE_RECLAIM, &data, &err);

		else

			ret = sev_do_cmd(SEV_CMD_SNP_PAGE_RECLAIM, &data, &err);



		if (ret)

			goto cleanup;



		ret = rmp_make_shared(__phys_to_pfn(paddr), PG_LEVEL_4K);

		if (ret)

			goto cleanup;

	}



	return 0;



cleanup:

	/*

	 * If there was a failure reclaiming the page then it is no longer safe

	 * to release it back to the system; leak it instead.

	 */

	snp_leak_pages(__phys_to_pfn(paddr), npages - i);

	return ret;

}



static int rmp_mark_pages_firmware(unsigned long paddr, unsigned int npages, bool locked)

{

	unsigned long pfn = __sme_clr(paddr) >> PAGE_SHIFT;

	int rc, i;



	for (i = 0; i < npages; i++, pfn++) {

		rc = rmp_make_private(pfn, 0, PG_LEVEL_4K, 0, true);

		if (rc)

			goto cleanup;

	}



	return 0;



cleanup:

	/*

	 * Try unrolling the firmware state changes by

	 * reclaiming the pages which were already changed to the

	 * firmware state.

	 */

	snp_reclaim_pages(paddr, i, locked);



	return rc;

}



static struct page *__snp_alloc_firmware_pages(gfp_t gfp_mask, int order)

{

	unsigned long npages = 1ul << order, paddr;

	struct sev_device *sev;

	struct page *page;



	if (!psp_master || !psp_master->sev_data)

		return NULL;



	page = alloc_pages(gfp_mask, order);

	if (!page)

		return NULL;



	/* If SEV-SNP is initialized then add the page in RMP table. */

	sev = psp_master->sev_data;

	if (!sev->snp_initialized)

		return page;



	paddr = __pa((unsigned long)page_address(page));

	if (rmp_mark_pages_firmware(paddr, npages, false))

		return NULL;



	return page;

}



void *snp_alloc_firmware_page(gfp_t gfp_mask)

{

	struct page *page;



	page = __snp_alloc_firmware_pages(gfp_mask, 0);



	return page ? page_address(page) : NULL;

}

EXPORT_SYMBOL_GPL(snp_alloc_firmware_page);



static void __snp_free_firmware_pages(struct page *page, int order, bool locked)

{

	struct sev_device *sev = psp_master->sev_data;

	unsigned long paddr, npages = 1ul << order;



	if (!page)

		return;



	paddr = __pa((unsigned long)page_address(page));

	if (sev->snp_initialized &&

	    snp_reclaim_pages(paddr, npages, locked))

		return;



	__free_pages(page, order);

}



void snp_free_firmware_page(void *addr)

{

	if (!addr)

		return;



	__snp_free_firmware_pages(virt_to_page(addr), 0, false);

}

EXPORT_SYMBOL_GPL(snp_free_firmware_page);



static void *sev_fw_alloc(unsigned long len)

{

	struct page *page;



	page = __snp_alloc_firmware_pages(GFP_KERNEL, get_order(len));

	if (!page)

		return NULL;



	return page_address(page);

}



static int __sev_do_cmd_locked(int cmd, void *data, int *psp_ret)

{

	struct psp_device *psp = psp_master;
@@ -456,7 +587,7 @@ static int __sev_init_locked(int *error) 
		data.tmr_address = __pa(sev_es_tmr);



		data.flags |= SEV_INIT_FLAGS_SEV_ES;

		data.tmr_len = SEV_ES_TMR_SIZE;

		data.tmr_len = sev_es_tmr_size;

	}



	return __sev_do_cmd_locked(SEV_CMD_INIT, &data, error);
@@ -479,7 +610,7 @@ static int __sev_init_ex_locked(int *error) 
		data.tmr_address = __pa(sev_es_tmr);



		data.flags |= SEV_INIT_FLAGS_SEV_ES;

		data.tmr_len = SEV_ES_TMR_SIZE;

		data.tmr_len = sev_es_tmr_size;

	}



	return __sev_do_cmd_locked(SEV_CMD_INIT_EX, &data, error);
@@ -623,9 +754,27 @@ static int __sev_snp_init_locked(int *error) 
	sev->snp_initialized = true;

	dev_dbg(sev->dev, "SEV-SNP firmware initialized\n");



	sev_es_tmr_size = SNP_TMR_SIZE;



	return rc;

}



static void __sev_platform_init_handle_tmr(struct sev_device *sev)

{

	if (sev_es_tmr)

		return;



	/* Obtain the TMR memory area for SEV-ES use */

	sev_es_tmr = sev_fw_alloc(sev_es_tmr_size);

	if (sev_es_tmr) {

		/* Must flush the cache before giving it to the firmware */

		if (!sev->snp_initialized)

			clflush_cache_range(sev_es_tmr, sev_es_tmr_size);

	} else {

			dev_warn(sev->dev, "SEV: TMR allocation failed, SEV-ES support unavailable\n");

	}

}



static int __sev_platform_init_locked(int *error)

{

	int rc, psp_ret = SEV_RET_NO_FW_CALL;
@@ -639,16 +788,7 @@ static int __sev_platform_init_locked(int *error) 
	if (sev->state == SEV_STATE_INIT)

		return 0;



	if (!sev_es_tmr) {

		/* Obtain the TMR memory area for SEV-ES use */

		sev_es_tmr = sev_fw_alloc(SEV_ES_TMR_SIZE);

		if (sev_es_tmr)

			/* Must flush the cache before giving it to the firmware */

			clflush_cache_range(sev_es_tmr, SEV_ES_TMR_SIZE);

		else

			dev_warn(sev->dev,

				 "SEV: TMR allocation failed, SEV-ES support unavailable\n");

		}

	__sev_platform_init_handle_tmr(sev);



	if (sev_init_ex_buffer) {

		rc = sev_read_init_ex_file();
@@ -1546,8 +1686,9 @@ static void sev_firmware_shutdown(struct sev_device *sev) 
		/* The TMR area was encrypted, flush it from the cache */

		wbinvd_on_all_cpus();



		free_pages((unsigned long)sev_es_tmr,

			   get_order(SEV_ES_TMR_SIZE));

		__snp_free_firmware_pages(virt_to_page(sev_es_tmr),

					  get_order(sev_es_tmr_size),

					  false);

		sev_es_tmr = NULL;

	}

include/linux/psp-sev.h

+9 −0
Original line number Diff line number Diff line
@@ -932,6 +932,8 @@ int sev_guest_decommission(struct sev_data_decommission *data, int *error); 
int sev_do_cmd(int cmd, void *data, int *psp_ret);



void *psp_copy_user_blob(u64 uaddr, u32 len);

void *snp_alloc_firmware_page(gfp_t mask);

void snp_free_firmware_page(void *addr);



#else	/* !CONFIG_CRYPTO_DEV_SP_PSP */
@@ -959,6 +961,13 @@ sev_issue_cmd_external_user(struct file *filep, unsigned int id, void *data, int 


static inline void *psp_copy_user_blob(u64 __user uaddr, u32 len) { return ERR_PTR(-EINVAL); }



static inline void *snp_alloc_firmware_page(gfp_t mask)

{

	return NULL;

}



static inline void snp_free_firmware_page(void *addr) { }



#endif	/* CONFIG_CRYPTO_DEV_SP_PSP */



#endif	/* __PSP_SEV_H__ */