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

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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: Brijesh Singh <brijesh.singh@amd.com>
Co-developed-by: Ashish Kalra <ashish.kalra@amd.com>
Signed-off-by: Ashish Kalra <ashish.kalra@amd.com>
Signed-off-by: Michael Roth <michael.roth@amd.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Link: https://lore.kernel.org/r/20240126041126.1927228-17-michael.roth@amd.com
This commit is contained in:
Brijesh Singh 2024-01-25 22:11:16 -06:00 committed by Borislav Petkov (AMD)
parent 8dac642999
commit 24512afa43
2 changed files with 176 additions and 26 deletions
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193
drivers/crypto/ccp/sev-dev.c
View File

@ -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;
}

9
include/linux/psp-sev.h
View File

@ -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__ */