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Drivers: hv: Don't remap addresses that are above shared_gpa_boundary

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With the vTOM bit now treated as a protection flag and not part of
the physical address, avoid remapping physical addresses with vTOM set
since technically such addresses aren't valid.  Use ioremap_cache()
instead of memremap() to ensure that the mapping provides decrypted
access, which will correctly set the vTOM bit as a protection flag.

While this change is not required for correctness with the current
implementation of memremap(), for general code hygiene it's better to
not depend on the mapping functions doing something reasonable with
a physical address that is out-of-range.

While here, fix typos in two error messages.

Signed-off-by: Michael Kelley <mikelley@microsoft.com>
Reviewed-by: Tianyu Lan <Tianyu.Lan@microsoft.com>
Link: https://lore.kernel.org/r/1679838727-87310-12-git-send-email-mikelley@microsoft.com
Signed-off-by: Wei Liu <wei.liu@kernel.org>
This commit is contained in:
Michael Kelley 2023-03-26 06:52:06 -07:00 committed by Wei Liu
parent 25727aaed6
commit 6afd9dc1a4
2 changed files with 18 additions and 12 deletions
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7
arch/x86/hyperv/hv_init.c
View File

@ -63,7 +63,10 @@ static int hyperv_init_ghcb(void)
* memory boundary and map it here.
*/
rdmsrl(MSR_AMD64_SEV_ES_GHCB, ghcb_gpa);
ghcb_va = memremap(ghcb_gpa, HV_HYP_PAGE_SIZE, MEMREMAP_WB);
/* Mask out vTOM bit. ioremap_cache() maps decrypted */
ghcb_gpa &= ~ms_hyperv.shared_gpa_boundary;
ghcb_va = (void *)ioremap_cache(ghcb_gpa, HV_HYP_PAGE_SIZE);
if (!ghcb_va)
return -ENOMEM;
@ -217,7 +220,7 @@ static int hv_cpu_die(unsigned int cpu)
if (hv_ghcb_pg) {
ghcb_va = (void **)this_cpu_ptr(hv_ghcb_pg);
if (*ghcb_va)
memunmap(*ghcb_va);
iounmap(*ghcb_va);
*ghcb_va = NULL;
}

23
drivers/hv/hv.c
View File

@ -217,11 +217,13 @@ void hv_synic_enable_regs(unsigned int cpu)
simp.simp_enabled = 1;
if (hv_isolation_type_snp() || hv_root_partition) {
/* Mask out vTOM bit. ioremap_cache() maps decrypted */
u64 base = (simp.base_simp_gpa << HV_HYP_PAGE_SHIFT) &
~ms_hyperv.shared_gpa_boundary;
hv_cpu->synic_message_page
= memremap(simp.base_simp_gpa << HV_HYP_PAGE_SHIFT,
HV_HYP_PAGE_SIZE, MEMREMAP_WB);
= (void *)ioremap_cache(base, HV_HYP_PAGE_SIZE);
if (!hv_cpu->synic_message_page)
pr_err("Fail to map syinc message page.\n");
pr_err("Fail to map synic message page.\n");
} else {
simp.base_simp_gpa = virt_to_phys(hv_cpu->synic_message_page)
>> HV_HYP_PAGE_SHIFT;
@ -234,12 +236,13 @@ void hv_synic_enable_regs(unsigned int cpu)
siefp.siefp_enabled = 1;
if (hv_isolation_type_snp() || hv_root_partition) {
hv_cpu->synic_event_page =
memremap(siefp.base_siefp_gpa << HV_HYP_PAGE_SHIFT,
HV_HYP_PAGE_SIZE, MEMREMAP_WB);
/* Mask out vTOM bit. ioremap_cache() maps decrypted */
u64 base = (siefp.base_siefp_gpa << HV_HYP_PAGE_SHIFT) &
~ms_hyperv.shared_gpa_boundary;
hv_cpu->synic_event_page
= (void *)ioremap_cache(base, HV_HYP_PAGE_SIZE);
if (!hv_cpu->synic_event_page)
pr_err("Fail to map syinc event page.\n");
pr_err("Fail to map synic event page.\n");
} else {
siefp.base_siefp_gpa = virt_to_phys(hv_cpu->synic_event_page)
>> HV_HYP_PAGE_SHIFT;
@ -316,7 +319,7 @@ void hv_synic_disable_regs(unsigned int cpu)
*/
simp.simp_enabled = 0;
if (hv_isolation_type_snp() || hv_root_partition) {
memunmap(hv_cpu->synic_message_page);
iounmap(hv_cpu->synic_message_page);
hv_cpu->synic_message_page = NULL;
} else {
simp.base_simp_gpa = 0;
@ -328,7 +331,7 @@ void hv_synic_disable_regs(unsigned int cpu)
siefp.siefp_enabled = 0;
if (hv_isolation_type_snp() || hv_root_partition) {
memunmap(hv_cpu->synic_event_page);
iounmap(hv_cpu->synic_event_page);
hv_cpu->synic_event_page = NULL;
} else {
siefp.base_siefp_gpa = 0;