Paolo Bonzini
2021-Nov-18 11:48 UTC
[PATCH] Fix SEV-ES INS/OUTS instructions for word, dword, and qword.
On 11/18/21 03:13, Michael Sterritt wrote:> Properly type the operands being passed to __put_user()/__get_user(). > Otherwise, these routines truncate data for dependent instructions > (e.g., INSW) and only read/write one byte. > > Tested: Tested by sending a string with `REP OUTSW` to a port and then > reading it back in with `REP INSW` on the same port. Previous behavior > was to only send and receive the first char of the size. For example, > word operations for "abcd" would only read/write "ac". With change, the > full string is now written and read back. > > Signed-off-by: Michael Sterritt <sterritt at google.com> > Reviewed-by: Marc Orr <marcorr at google.com> > Reviewed-by: Peter Gonda <pgonda at google.com> > --- > arch/x86/kernel/sev.c | 57 +++++++++++++++++++++++++++++-------------- > 1 file changed, 39 insertions(+), 18 deletions(-) > > diff --git a/arch/x86/kernel/sev.c b/arch/x86/kernel/sev.c > index 74f0ec955384..a9fc2ac7a8bd 100644 > --- a/arch/x86/kernel/sev.c > +++ b/arch/x86/kernel/sev.c > @@ -294,11 +294,6 @@ static enum es_result vc_write_mem(struct es_em_ctxt *ctxt, > char *dst, char *buf, size_t size) > { > unsigned long error_code = X86_PF_PROT | X86_PF_WRITE; > - char __user *target = (char __user *)dst; > - u64 d8; > - u32 d4; > - u16 d2; > - u8 d1; > > /* > * This function uses __put_user() independent of whether kernel or user > @@ -320,26 +315,42 @@ static enum es_result vc_write_mem(struct es_em_ctxt *ctxt, > * instructions here would cause infinite nesting. > */ > switch (size) { > - case 1: > + case 1: { > + u8 d1; > + u8 __user *target = (u8 __user *)dst; > + > memcpy(&d1, buf, 1); > if (__put_user(d1, target)) > goto fault; > break; > - case 2: > + } > + case 2: { > + u16 d2; > + u16 __user *target = (u16 __user *)dst; > + > memcpy(&d2, buf, 2); > if (__put_user(d2, target)) > goto fault; > break; > - case 4: > + } > + case 4: { > + u32 d4; > + u32 __user *target = (u32 __user *)dst; > + > memcpy(&d4, buf, 4); > if (__put_user(d4, target)) > goto fault; > break; > - case 8: > + } > + case 8: { > + u64 d8; > + u64 __user *target = (u64 __user *)dst; > + > memcpy(&d8, buf, 8); > if (__put_user(d8, target)) > goto fault; > break; > + } > default: > WARN_ONCE(1, "%s: Invalid size: %zu\n", __func__, size); > return ES_UNSUPPORTED; > @@ -362,11 +373,6 @@ static enum es_result vc_read_mem(struct es_em_ctxt *ctxt, > char *src, char *buf, size_t size) > { > unsigned long error_code = X86_PF_PROT; > - char __user *s = (char __user *)src; > - u64 d8; > - u32 d4; > - u16 d2; > - u8 d1; > > /* > * This function uses __get_user() independent of whether kernel or user > @@ -388,26 +394,41 @@ static enum es_result vc_read_mem(struct es_em_ctxt *ctxt, > * instructions here would cause infinite nesting. > */ > switch (size) { > - case 1: > + case 1: { > + u8 d1; > + u8 __user *s = (u8 __user *)src; > + > if (__get_user(d1, s)) > goto fault; > memcpy(buf, &d1, 1); > break; > - case 2: > + } > + case 2: { > + u16 d2; > + u16 __user *s = (u16 __user *)src; > + > if (__get_user(d2, s)) > goto fault; > memcpy(buf, &d2, 2); > break; > - case 4: > + } > + case 4: { > + u32 d4; > + u32 __user *s = (u32 __user *)src; > + > if (__get_user(d4, s)) > goto fault; > memcpy(buf, &d4, 4); > break; > - case 8: > + } > + case 8: { > + u64 d8; > + u64 __user *s = (u64 __user *)src; > if (__get_user(d8, s)) > goto fault; > memcpy(buf, &d8, 8); > break; > + } > default: > WARN_ONCE(1, "%s: Invalid size: %zu\n", __func__, size); > return ES_UNSUPPORTED; >Reviewed-by: Paolo Bonzini <pbonzini at redhat.com>