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-rw-r--r--arch/x86/coco/sev/core.c112
-rw-r--r--arch/x86/coco/sev/vc-handle.c40
2 files changed, 95 insertions, 57 deletions
diff --git a/arch/x86/coco/sev/core.c b/arch/x86/coco/sev/core.c
index 7543a8b52c67..14ef5908fb27 100644
--- a/arch/x86/coco/sev/core.c
+++ b/arch/x86/coco/sev/core.c
@@ -227,6 +227,7 @@ static u64 svsm_build_ca_from_pfn_range(u64 pfn, u64 pfn_end, bool action,
pe->page_size = RMP_PG_SIZE_4K;
pe->action = action;
pe->ignore_cf = 0;
+ pe->rsvd = 0;
pe->pfn = pfn;
pe++;
@@ -257,6 +258,7 @@ static int svsm_build_ca_from_psc_desc(struct snp_psc_desc *desc, unsigned int d
pe->page_size = e->pagesize ? RMP_PG_SIZE_2M : RMP_PG_SIZE_4K;
pe->action = e->operation == SNP_PAGE_STATE_PRIVATE;
pe->ignore_cf = 0;
+ pe->rsvd = 0;
pe->pfn = e->gfn;
pe++;
@@ -358,10 +360,31 @@ static void svsm_pval_pages(struct snp_psc_desc *desc)
static void pvalidate_pages(struct snp_psc_desc *desc)
{
+ struct psc_entry *e;
+ unsigned int i;
+
if (snp_vmpl)
svsm_pval_pages(desc);
else
pval_pages(desc);
+
+ /*
+ * If not affected by the cache-coherency vulnerability there is no need
+ * to perform the cache eviction mitigation.
+ */
+ if (cpu_feature_enabled(X86_FEATURE_COHERENCY_SFW_NO))
+ return;
+
+ for (i = 0; i <= desc->hdr.end_entry; i++) {
+ e = &desc->entries[i];
+
+ /*
+ * If validating memory (making it private) perform the cache
+ * eviction mitigation.
+ */
+ if (e->operation == SNP_PAGE_STATE_PRIVATE)
+ sev_evict_cache(pfn_to_kaddr(e->gfn), e->pagesize ? 512 : 1);
+ }
}
static int vmgexit_psc(struct ghcb *ghcb, struct snp_psc_desc *desc)
@@ -1045,11 +1068,13 @@ int __init sev_es_setup_ap_jump_table(struct real_mode_header *rmh)
* This is needed by the OVMF UEFI firmware which will use whatever it finds in
* the GHCB MSR as its GHCB to talk to the hypervisor. So make sure the per-cpu
* runtime GHCBs used by the kernel are also mapped in the EFI page-table.
+ *
+ * When running under SVSM the CA page is needed too, so map it as well.
*/
-int __init sev_es_efi_map_ghcbs(pgd_t *pgd)
+int __init sev_es_efi_map_ghcbs_cas(pgd_t *pgd)
{
+ unsigned long address, pflags, pflags_enc;
struct sev_es_runtime_data *data;
- unsigned long address, pflags;
int cpu;
u64 pfn;
@@ -1057,6 +1082,7 @@ int __init sev_es_efi_map_ghcbs(pgd_t *pgd)
return 0;
pflags = _PAGE_NX | _PAGE_RW;
+ pflags_enc = cc_mkenc(pflags);
for_each_possible_cpu(cpu) {
data = per_cpu(runtime_data, cpu);
@@ -1066,6 +1092,16 @@ int __init sev_es_efi_map_ghcbs(pgd_t *pgd)
if (kernel_map_pages_in_pgd(pgd, pfn, address, 1, pflags))
return 1;
+
+ if (snp_vmpl) {
+ address = per_cpu(svsm_caa_pa, cpu);
+ if (!address)
+ return 1;
+
+ pfn = address >> PAGE_SHIFT;
+ if (kernel_map_pages_in_pgd(pgd, pfn, address, 1, pflags_enc))
+ return 1;
+ }
}
return 0;
@@ -1389,16 +1425,16 @@ int snp_issue_svsm_attest_req(u64 call_id, struct svsm_call *call,
}
EXPORT_SYMBOL_GPL(snp_issue_svsm_attest_req);
-static int snp_issue_guest_request(struct snp_guest_req *req, struct snp_req_data *input,
- struct snp_guest_request_ioctl *rio)
+static int snp_issue_guest_request(struct snp_guest_req *req)
{
+ struct snp_req_data *input = &req->input;
struct ghcb_state state;
struct es_em_ctxt ctxt;
unsigned long flags;
struct ghcb *ghcb;
int ret;
- rio->exitinfo2 = SEV_RET_NO_FW_CALL;
+ req->exitinfo2 = SEV_RET_NO_FW_CALL;
/*
* __sev_get_ghcb() needs to run with IRQs disabled because it is using
@@ -1423,8 +1459,8 @@ static int snp_issue_guest_request(struct snp_guest_req *req, struct snp_req_dat
if (ret)
goto e_put;
- rio->exitinfo2 = ghcb->save.sw_exit_info_2;
- switch (rio->exitinfo2) {
+ req->exitinfo2 = ghcb->save.sw_exit_info_2;
+ switch (req->exitinfo2) {
case 0:
break;
@@ -1919,8 +1955,7 @@ static int enc_payload(struct snp_msg_desc *mdesc, u64 seqno, struct snp_guest_r
return 0;
}
-static int __handle_guest_request(struct snp_msg_desc *mdesc, struct snp_guest_req *req,
- struct snp_guest_request_ioctl *rio)
+static int __handle_guest_request(struct snp_msg_desc *mdesc, struct snp_guest_req *req)
{
unsigned long req_start = jiffies;
unsigned int override_npages = 0;
@@ -1934,7 +1969,7 @@ retry_request:
* sequence number must be incremented or the VMPCK must be deleted to
* prevent reuse of the IV.
*/
- rc = snp_issue_guest_request(req, &req->input, rio);
+ rc = snp_issue_guest_request(req);
switch (rc) {
case -ENOSPC:
/*
@@ -1987,7 +2022,7 @@ retry_request:
snp_inc_msg_seqno(mdesc);
if (override_err) {
- rio->exitinfo2 = override_err;
+ req->exitinfo2 = override_err;
/*
* If an extended guest request was issued and the supplied certificate
@@ -2005,12 +2040,20 @@ retry_request:
return rc;
}
-int snp_send_guest_request(struct snp_msg_desc *mdesc, struct snp_guest_req *req,
- struct snp_guest_request_ioctl *rio)
+int snp_send_guest_request(struct snp_msg_desc *mdesc, struct snp_guest_req *req)
{
u64 seqno;
int rc;
+ /*
+ * enc_payload() calls aesgcm_encrypt(), which can potentially offload to HW.
+ * The offload's DMA SG list of data to encrypt has to be in linear mapping.
+ */
+ if (!virt_addr_valid(req->req_buf) || !virt_addr_valid(req->resp_buf)) {
+ pr_warn("AES-GSM buffers must be in linear mapping");
+ return -EINVAL;
+ }
+
guard(mutex)(&snp_cmd_mutex);
/* Check if the VMPCK is not empty */
@@ -2043,14 +2086,14 @@ int snp_send_guest_request(struct snp_msg_desc *mdesc, struct snp_guest_req *req
req->input.resp_gpa = __pa(mdesc->response);
req->input.data_gpa = req->certs_data ? __pa(req->certs_data) : 0;
- rc = __handle_guest_request(mdesc, req, rio);
+ rc = __handle_guest_request(mdesc, req);
if (rc) {
if (rc == -EIO &&
- rio->exitinfo2 == SNP_GUEST_VMM_ERR(SNP_GUEST_VMM_ERR_INVALID_LEN))
+ req->exitinfo2 == SNP_GUEST_VMM_ERR(SNP_GUEST_VMM_ERR_INVALID_LEN))
return rc;
pr_alert("Detected error from ASP request. rc: %d, exitinfo2: 0x%llx\n",
- rc, rio->exitinfo2);
+ rc, req->exitinfo2);
snp_disable_vmpck(mdesc);
return rc;
@@ -2069,11 +2112,10 @@ EXPORT_SYMBOL_GPL(snp_send_guest_request);
static int __init snp_get_tsc_info(void)
{
- struct snp_guest_request_ioctl *rio;
struct snp_tsc_info_resp *tsc_resp;
struct snp_tsc_info_req *tsc_req;
struct snp_msg_desc *mdesc;
- struct snp_guest_req *req;
+ struct snp_guest_req req = {};
int rc = -ENOMEM;
tsc_req = kzalloc(sizeof(*tsc_req), GFP_KERNEL);
@@ -2089,32 +2131,24 @@ static int __init snp_get_tsc_info(void)
if (!tsc_resp)
goto e_free_tsc_req;
- req = kzalloc(sizeof(*req), GFP_KERNEL);
- if (!req)
- goto e_free_tsc_resp;
-
- rio = kzalloc(sizeof(*rio), GFP_KERNEL);
- if (!rio)
- goto e_free_req;
-
mdesc = snp_msg_alloc();
if (IS_ERR_OR_NULL(mdesc))
- goto e_free_rio;
+ goto e_free_tsc_resp;
rc = snp_msg_init(mdesc, snp_vmpl);
if (rc)
goto e_free_mdesc;
- req->msg_version = MSG_HDR_VER;
- req->msg_type = SNP_MSG_TSC_INFO_REQ;
- req->vmpck_id = snp_vmpl;
- req->req_buf = tsc_req;
- req->req_sz = sizeof(*tsc_req);
- req->resp_buf = (void *)tsc_resp;
- req->resp_sz = sizeof(*tsc_resp) + AUTHTAG_LEN;
- req->exit_code = SVM_VMGEXIT_GUEST_REQUEST;
+ req.msg_version = MSG_HDR_VER;
+ req.msg_type = SNP_MSG_TSC_INFO_REQ;
+ req.vmpck_id = snp_vmpl;
+ req.req_buf = tsc_req;
+ req.req_sz = sizeof(*tsc_req);
+ req.resp_buf = (void *)tsc_resp;
+ req.resp_sz = sizeof(*tsc_resp) + AUTHTAG_LEN;
+ req.exit_code = SVM_VMGEXIT_GUEST_REQUEST;
- rc = snp_send_guest_request(mdesc, req, rio);
+ rc = snp_send_guest_request(mdesc, &req);
if (rc)
goto e_request;
@@ -2135,11 +2169,7 @@ e_request:
memzero_explicit(tsc_resp, sizeof(*tsc_resp) + AUTHTAG_LEN);
e_free_mdesc:
snp_msg_free(mdesc);
-e_free_rio:
- kfree(rio);
-e_free_req:
- kfree(req);
- e_free_tsc_resp:
+e_free_tsc_resp:
kfree(tsc_resp);
e_free_tsc_req:
kfree(tsc_req);
diff --git a/arch/x86/coco/sev/vc-handle.c b/arch/x86/coco/sev/vc-handle.c
index 0989d98da130..c3b4acbde0d8 100644
--- a/arch/x86/coco/sev/vc-handle.c
+++ b/arch/x86/coco/sev/vc-handle.c
@@ -17,6 +17,7 @@
#include <linux/mm.h>
#include <linux/io.h>
#include <linux/psp-sev.h>
+#include <linux/efi.h>
#include <uapi/linux/sev-guest.h>
#include <asm/init.h>
@@ -178,9 +179,15 @@ static enum es_result __vc_decode_kern_insn(struct es_em_ctxt *ctxt)
return ES_OK;
}
+/*
+ * User instruction decoding is also required for the EFI runtime. Even though
+ * the EFI runtime is running in kernel mode, it uses special EFI virtual
+ * address mappings that require the use of efi_mm to properly address and
+ * decode.
+ */
static enum es_result vc_decode_insn(struct es_em_ctxt *ctxt)
{
- if (user_mode(ctxt->regs))
+ if (user_mode(ctxt->regs) || mm_is_efi(current->active_mm))
return __vc_decode_user_insn(ctxt);
else
return __vc_decode_kern_insn(ctxt);
@@ -364,29 +371,30 @@ static enum es_result __vc_handle_msr_caa(struct pt_regs *regs, bool write)
* executing with Secure TSC enabled, so special handling is required for
* accesses of MSR_IA32_TSC and MSR_AMD64_GUEST_TSC_FREQ.
*/
-static enum es_result __vc_handle_secure_tsc_msrs(struct pt_regs *regs, bool write)
+static enum es_result __vc_handle_secure_tsc_msrs(struct es_em_ctxt *ctxt, bool write)
{
+ struct pt_regs *regs = ctxt->regs;
u64 tsc;
/*
- * GUEST_TSC_FREQ should not be intercepted when Secure TSC is enabled.
- * Terminate the SNP guest when the interception is enabled.
+ * Writing to MSR_IA32_TSC can cause subsequent reads of the TSC to
+ * return undefined values, and GUEST_TSC_FREQ is read-only. Generate
+ * a #GP on all writes.
*/
- if (regs->cx == MSR_AMD64_GUEST_TSC_FREQ)
- return ES_VMM_ERROR;
+ if (write) {
+ ctxt->fi.vector = X86_TRAP_GP;
+ ctxt->fi.error_code = 0;
+ return ES_EXCEPTION;
+ }
/*
- * Writes: Writing to MSR_IA32_TSC can cause subsequent reads of the TSC
- * to return undefined values, so ignore all writes.
- *
- * Reads: Reads of MSR_IA32_TSC should return the current TSC value, use
- * the value returned by rdtsc_ordered().
+ * GUEST_TSC_FREQ read should not be intercepted when Secure TSC is
+ * enabled. Terminate the guest if a read is attempted.
*/
- if (write) {
- WARN_ONCE(1, "TSC MSR writes are verboten!\n");
- return ES_OK;
- }
+ if (regs->cx == MSR_AMD64_GUEST_TSC_FREQ)
+ return ES_VMM_ERROR;
+ /* Reads of MSR_IA32_TSC should return the current TSC value. */
tsc = rdtsc_ordered();
regs->ax = lower_32_bits(tsc);
regs->dx = upper_32_bits(tsc);
@@ -409,7 +417,7 @@ static enum es_result vc_handle_msr(struct ghcb *ghcb, struct es_em_ctxt *ctxt)
case MSR_IA32_TSC:
case MSR_AMD64_GUEST_TSC_FREQ:
if (sev_status & MSR_AMD64_SNP_SECURE_TSC)
- return __vc_handle_secure_tsc_msrs(regs, write);
+ return __vc_handle_secure_tsc_msrs(ctxt, write);
break;
default:
break;
generated by cgit (git 2.34.1) at 2025-08-19 18:44:12 +0000