Messages in this thread | | | Date | Mon, 14 Nov 2022 15:01:11 -0600 | Subject | Re: [PATCH v8 2/4] x86/sev: Change snp_guest_issue_request's fw_err | From | Tom Lendacky <> |
| |
On 11/4/22 18:00, Dionna Glaze wrote: > The GHCB specification declares that the firmware error value for a > guest request will be stored in the lower 32 bits of EXIT_INFO_2. > The upper 32 bits are for the VMM's own error code. The fw_err argument > is thus a misnomer, and callers will need access to all 64 bits. > > The type of unsigned long also causes problems, since sw_exit_info2 is > u64 (unsigned long long) vs the argument's previous unsigned long*. > The signature change requires the follow-up change to > drivers/virt/coco/sev-guest to use the new expected type in order to > compile. > > The firmware might not even be called, so we bookend the call with the > no firmware call error and clearing the error. > > Cc: Tom Lendacky <Thomas.Lendacky@amd.com> > Cc: Paolo Bonzini <pbonzini@redhat.com> > Cc: Joerg Roedel <jroedel@suse.de> > Cc: Peter Gonda <pgonda@google.com> > Cc: Thomas Gleixner <tglx@linutronix.de> > Cc: Dave Hansen <dave.hansen@linux.intel.com> > Cc: Ingo Molnar <mingo@redhat.com> > Cc: Borislav Petkov <bp@alien8.de> > Cc: "H. Peter Anvin" <hpa@zytor.com> > Cc: Venu Busireddy <venu.busireddy@oracle.com> > Cc: Michael Roth <michael.roth@amd.com> > Cc: "Kirill A. Shutemov" <kirill@shutemov.name> > Cc: Michael Sterritt <sterritt@google.com> > > Fixes: d5af44dde546 ("x86/sev: Provide support for SNP guest request NAEs") > Signed-off-by: Dionna Glaze <dionnaglaze@google.com>
Reviewed-by: Tom Lendacky <thomas.lendacky@amd.com>
> --- > arch/x86/include/asm/sev.h | 4 ++-- > arch/x86/kernel/sev.c | 10 ++++++---- > 2 files changed, 8 insertions(+), 6 deletions(-) > > diff --git a/arch/x86/include/asm/sev.h b/arch/x86/include/asm/sev.h > index ebc271bb6d8e..05de34d10d89 100644 > --- a/arch/x86/include/asm/sev.h > +++ b/arch/x86/include/asm/sev.h > @@ -196,7 +196,7 @@ void snp_set_memory_private(unsigned long vaddr, unsigned int npages); > void snp_set_wakeup_secondary_cpu(void); > bool snp_init(struct boot_params *bp); > void __init __noreturn snp_abort(void); > -int snp_issue_guest_request(u64 exit_code, struct snp_req_data *input, unsigned long *fw_err); > +int snp_issue_guest_request(u64 exit_code, struct snp_req_data *input, u64 *exitinfo2); > #else > static inline void sev_es_ist_enter(struct pt_regs *regs) { } > static inline void sev_es_ist_exit(void) { } > @@ -217,7 +217,7 @@ static inline void snp_set_wakeup_secondary_cpu(void) { } > static inline bool snp_init(struct boot_params *bp) { return false; } > static inline void snp_abort(void) { } > static inline int snp_issue_guest_request(u64 exit_code, struct snp_req_data *input, > - unsigned long *fw_err) > + u64 *exitinfo2) > { > return -ENOTTY; > } > diff --git a/arch/x86/kernel/sev.c b/arch/x86/kernel/sev.c > index a428c62330d3..148f17cb07b5 100644 > --- a/arch/x86/kernel/sev.c > +++ b/arch/x86/kernel/sev.c > @@ -22,6 +22,7 @@ > #include <linux/efi.h> > #include <linux/platform_device.h> > #include <linux/io.h> > +#include <linux/psp-sev.h> > > #include <asm/cpu_entry_area.h> > #include <asm/stacktrace.h> > @@ -2175,7 +2176,7 @@ static int __init init_sev_config(char *str) > } > __setup("sev=", init_sev_config); > > -int snp_issue_guest_request(u64 exit_code, struct snp_req_data *input, unsigned long *fw_err) > +int snp_issue_guest_request(u64 exit_code, struct snp_req_data *input, u64 *exitinfo2) > { > struct ghcb_state state; > struct es_em_ctxt ctxt; > @@ -2186,9 +2187,11 @@ int snp_issue_guest_request(u64 exit_code, struct snp_req_data *input, unsigned > if (!cc_platform_has(CC_ATTR_GUEST_SEV_SNP)) > return -ENODEV; > > - if (!fw_err) > + if (!exitinfo2) > return -EINVAL; > > + *exitinfo2 = SEV_RET_NO_FW_CALL; > + > /* > * __sev_get_ghcb() needs to run with IRQs disabled because it is using > * a per-CPU GHCB. > @@ -2212,14 +2215,13 @@ int snp_issue_guest_request(u64 exit_code, struct snp_req_data *input, unsigned > if (ret) > goto e_put; > > + *exitinfo2 = ghcb->save.sw_exit_info_2; > if (ghcb->save.sw_exit_info_2) { > /* Number of expected pages are returned in RBX */ > if (exit_code == SVM_VMGEXIT_EXT_GUEST_REQUEST && > ghcb->save.sw_exit_info_2 == SNP_GUEST_REQ_INVALID_LEN) > input->data_npages = ghcb_get_rbx(ghcb); > > - *fw_err = ghcb->save.sw_exit_info_2; > - > ret = -EIO; > } >
| |