| Message ID | 86636401aa34f9c64e674a53d49859930a227d10.1729066788.git.bertrand.marquis@arm.com (mailing list archive) |
|---|---|
| State | New |
| Headers | show |
| Series | xen/arm: ffa: Improvements and fixes | expand |
Hi Bertrand, On Wed, Oct 16, 2024 at 10:32 AM Bertrand Marquis <bertrand.marquis@arm.com> wrote: > > Fix FFA version negotiation with the firmware to follow the > specification guidance more closely (see FF-A Specification Version 1.1 > in chapter 13.2.1). > When the firmware returns OK we can have several cases: > - the version requested is accepted but the firmware supports a greater > one in the same major. > - the firmware supports a greater major version. It could still return > OK even if the version requested is not accepted. Reject it. > - the firmware supports a lower version. It will return OK and give that > version. Check if we support it and use it or reject it if we do not. > > Adapt the code to: > - reject any version lower than the one we support or not with the same > major version > - use the version returned if in our supported range (currently 1.1 > only) > - use 1.1 if the version returned is greater. > > Also adapt the handling of version requests from VM: > - use our version if same major but greater minor is requested > - use requested version if same major but lower minor is requested > - do not use if incompatible major is requested > - always return our version without error to the requester > > [1] https://developer.arm.com/documentation/den0077/e/ > > Signed-off-by: Bertrand Marquis <bertrand.marquis@arm.com> > --- > Changes in v2: > - add link in commit message and code to the version and chapter of > the spec. > - fix comment coding style > - introduce macros to get the major and minor of a version > - add BUILD_BUG_ON to validate that the SPMC version we want is > compatible with our own version > - rework version testing and selecting to be clearer by discarding > different major or version lower than what we want and then selecting > based on the minor version. > - fix get_version handling to be more generic > --- > xen/arch/arm/tee/ffa.c | 54 +++++++++++++++++++++++++--------- > xen/arch/arm/tee/ffa_private.h | 3 ++ > 2 files changed, 43 insertions(+), 14 deletions(-) Looks good. Reviewed-by: Jens Wiklander <jens.wiklander@linaro.org> Cheers, Jens > > diff --git a/xen/arch/arm/tee/ffa.c b/xen/arch/arm/tee/ffa.c > index dde932422ecf..1ee6b2895e92 100644 > --- a/xen/arch/arm/tee/ffa.c > +++ b/xen/arch/arm/tee/ffa.c > @@ -148,13 +148,20 @@ static void handle_version(struct cpu_user_regs *regs) > struct ffa_ctx *ctx = d->arch.tee; > uint32_t vers = get_user_reg(regs, 1); > > - if ( vers < FFA_VERSION_1_1 ) > - vers = FFA_VERSION_1_0; > - else > - vers = FFA_VERSION_1_1; > - > - ctx->guest_vers = vers; > - ffa_set_regs(regs, vers, 0, 0, 0, 0, 0, 0, 0); > + /* > + * Guest will use the version it requested if it is our major and minor > + * lower or equals to ours. If the minor is greater, our version will be > + * used. > + * In any case return our version to the caller. > + */ > + if ( FFA_VERSION_MAJOR(vers) == FFA_MY_VERSION_MAJOR ) > + { > + if ( FFA_VERSION_MINOR(vers) > FFA_MY_VERSION_MINOR ) > + ctx->guest_vers = FFA_MY_VERSION; > + else > + ctx->guest_vers = vers; > + } > + ffa_set_regs(regs, FFA_MY_VERSION, 0, 0, 0, 0, 0, 0, 0); > } > > static void handle_msg_send_direct_req(struct cpu_user_regs *regs, uint32_t fid) > @@ -537,18 +544,39 @@ static bool ffa_probe(void) > goto err_no_fw; > } > > - if ( vers < FFA_MIN_SPMC_VERSION || vers > FFA_MY_VERSION ) > + /* Some sanity check in case we update the version we support */ > + BUILD_BUG_ON(FFA_MIN_SPMC_VERSION > FFA_MY_VERSION); > + BUILD_BUG_ON(FFA_VERSION_MAJOR(FFA_MIN_SPMC_VERSION) != > + FFA_MY_VERSION_MAJOR); > + > + major_vers = FFA_VERSION_MAJOR(vers); > + minor_vers = FFA_VERSION_MINOR(vers); > + > + if ( major_vers != FFA_MY_VERSION_MAJOR || > + minor_vers < FFA_VERSION_MINOR(FFA_MIN_SPMC_VERSION) ) > { > - printk(XENLOG_ERR "ffa: Incompatible version %#x found\n", vers); > + printk(XENLOG_ERR "ffa: Incompatible firmware version %u.%u\n", > + major_vers, minor_vers); > goto err_no_fw; > } > > - major_vers = (vers >> FFA_VERSION_MAJOR_SHIFT) > - & FFA_VERSION_MAJOR_MASK; > - minor_vers = vers & FFA_VERSION_MINOR_MASK; > printk(XENLOG_INFO "ARM FF-A Firmware version %u.%u\n", > major_vers, minor_vers); > > + /* > + * If the call succeed and the version returned is higher or equal to > + * the one Xen requested, the version requested by Xen will be the one > + * used. If the version returned is lower but compatible with Xen, Xen > + * will use that version instead. > + * A version with a different major or lower than the minimum version > + * we support is rejected before. > + * See https://developer.arm.com/documentation/den0077/e/ chapter 13.2.1 > + */ > + if ( minor_vers > FFA_MY_VERSION_MINOR ) > + ffa_fw_version = FFA_MY_VERSION; > + else > + ffa_fw_version = vers; > + > /* > * At the moment domains must support the same features used by Xen. > * TODO: Rework the code to allow domain to use a subset of the > @@ -564,8 +592,6 @@ static bool ffa_probe(void) > } > } > > - ffa_fw_version = vers; > - > if ( !ffa_rxtx_init() ) > { > printk(XENLOG_ERR "ffa: Error during RXTX buffer init\n"); > diff --git a/xen/arch/arm/tee/ffa_private.h b/xen/arch/arm/tee/ffa_private.h > index 7c6b06f686fc..045d9c4a0b56 100644 > --- a/xen/arch/arm/tee/ffa_private.h > +++ b/xen/arch/arm/tee/ffa_private.h > @@ -35,6 +35,9 @@ > #define MAKE_FFA_VERSION(major, minor) \ > ((((major) & FFA_VERSION_MAJOR_MASK) << FFA_VERSION_MAJOR_SHIFT) | \ > ((minor) & FFA_VERSION_MINOR_MASK)) > +#define FFA_VERSION_MAJOR(vers) (((vers) >> FFA_VERSION_MAJOR_SHIFT) & \ > + FFA_VERSION_MAJOR_MASK) > +#define FFA_VERSION_MINOR(vers) ((vers) & FFA_VERSION_MINOR_MASK) > > #define FFA_VERSION_1_0 MAKE_FFA_VERSION(1, 0) > #define FFA_VERSION_1_1 MAKE_FFA_VERSION(1, 1) > -- > 2.47.0 >
diff --git a/xen/arch/arm/tee/ffa.c b/xen/arch/arm/tee/ffa.c index dde932422ecf..1ee6b2895e92 100644 --- a/xen/arch/arm/tee/ffa.c +++ b/xen/arch/arm/tee/ffa.c @@ -148,13 +148,20 @@ static void handle_version(struct cpu_user_regs *regs) struct ffa_ctx *ctx = d->arch.tee; uint32_t vers = get_user_reg(regs, 1); - if ( vers < FFA_VERSION_1_1 ) - vers = FFA_VERSION_1_0; - else - vers = FFA_VERSION_1_1; - - ctx->guest_vers = vers; - ffa_set_regs(regs, vers, 0, 0, 0, 0, 0, 0, 0); + /* + * Guest will use the version it requested if it is our major and minor + * lower or equals to ours. If the minor is greater, our version will be + * used. + * In any case return our version to the caller. + */ + if ( FFA_VERSION_MAJOR(vers) == FFA_MY_VERSION_MAJOR ) + { + if ( FFA_VERSION_MINOR(vers) > FFA_MY_VERSION_MINOR ) + ctx->guest_vers = FFA_MY_VERSION; + else + ctx->guest_vers = vers; + } + ffa_set_regs(regs, FFA_MY_VERSION, 0, 0, 0, 0, 0, 0, 0); } static void handle_msg_send_direct_req(struct cpu_user_regs *regs, uint32_t fid) @@ -537,18 +544,39 @@ static bool ffa_probe(void) goto err_no_fw; } - if ( vers < FFA_MIN_SPMC_VERSION || vers > FFA_MY_VERSION ) + /* Some sanity check in case we update the version we support */ + BUILD_BUG_ON(FFA_MIN_SPMC_VERSION > FFA_MY_VERSION); + BUILD_BUG_ON(FFA_VERSION_MAJOR(FFA_MIN_SPMC_VERSION) != + FFA_MY_VERSION_MAJOR); + + major_vers = FFA_VERSION_MAJOR(vers); + minor_vers = FFA_VERSION_MINOR(vers); + + if ( major_vers != FFA_MY_VERSION_MAJOR || + minor_vers < FFA_VERSION_MINOR(FFA_MIN_SPMC_VERSION) ) { - printk(XENLOG_ERR "ffa: Incompatible version %#x found\n", vers); + printk(XENLOG_ERR "ffa: Incompatible firmware version %u.%u\n", + major_vers, minor_vers); goto err_no_fw; } - major_vers = (vers >> FFA_VERSION_MAJOR_SHIFT) - & FFA_VERSION_MAJOR_MASK; - minor_vers = vers & FFA_VERSION_MINOR_MASK; printk(XENLOG_INFO "ARM FF-A Firmware version %u.%u\n", major_vers, minor_vers); + /* + * If the call succeed and the version returned is higher or equal to + * the one Xen requested, the version requested by Xen will be the one + * used. If the version returned is lower but compatible with Xen, Xen + * will use that version instead. + * A version with a different major or lower than the minimum version + * we support is rejected before. + * See https://developer.arm.com/documentation/den0077/e/ chapter 13.2.1 + */ + if ( minor_vers > FFA_MY_VERSION_MINOR ) + ffa_fw_version = FFA_MY_VERSION; + else + ffa_fw_version = vers; + /* * At the moment domains must support the same features used by Xen. * TODO: Rework the code to allow domain to use a subset of the @@ -564,8 +592,6 @@ static bool ffa_probe(void) } } - ffa_fw_version = vers; - if ( !ffa_rxtx_init() ) { printk(XENLOG_ERR "ffa: Error during RXTX buffer init\n"); diff --git a/xen/arch/arm/tee/ffa_private.h b/xen/arch/arm/tee/ffa_private.h index 7c6b06f686fc..045d9c4a0b56 100644 --- a/xen/arch/arm/tee/ffa_private.h +++ b/xen/arch/arm/tee/ffa_private.h @@ -35,6 +35,9 @@ #define MAKE_FFA_VERSION(major, minor) \ ((((major) & FFA_VERSION_MAJOR_MASK) << FFA_VERSION_MAJOR_SHIFT) | \ ((minor) & FFA_VERSION_MINOR_MASK)) +#define FFA_VERSION_MAJOR(vers) (((vers) >> FFA_VERSION_MAJOR_SHIFT) & \ + FFA_VERSION_MAJOR_MASK) +#define FFA_VERSION_MINOR(vers) ((vers) & FFA_VERSION_MINOR_MASK) #define FFA_VERSION_1_0 MAKE_FFA_VERSION(1, 0) #define FFA_VERSION_1_1 MAKE_FFA_VERSION(1, 1)
Fix FFA version negotiation with the firmware to follow the specification guidance more closely (see FF-A Specification Version 1.1 in chapter 13.2.1). When the firmware returns OK we can have several cases: - the version requested is accepted but the firmware supports a greater one in the same major. - the firmware supports a greater major version. It could still return OK even if the version requested is not accepted. Reject it. - the firmware supports a lower version. It will return OK and give that version. Check if we support it and use it or reject it if we do not. Adapt the code to: - reject any version lower than the one we support or not with the same major version - use the version returned if in our supported range (currently 1.1 only) - use 1.1 if the version returned is greater. Also adapt the handling of version requests from VM: - use our version if same major but greater minor is requested - use requested version if same major but lower minor is requested - do not use if incompatible major is requested - always return our version without error to the requester [1] https://developer.arm.com/documentation/den0077/e/ Signed-off-by: Bertrand Marquis <bertrand.marquis@arm.com> --- Changes in v2: - add link in commit message and code to the version and chapter of the spec. - fix comment coding style - introduce macros to get the major and minor of a version - add BUILD_BUG_ON to validate that the SPMC version we want is compatible with our own version - rework version testing and selecting to be clearer by discarding different major or version lower than what we want and then selecting based on the minor version. - fix get_version handling to be more generic --- xen/arch/arm/tee/ffa.c | 54 +++++++++++++++++++++++++--------- xen/arch/arm/tee/ffa_private.h | 3 ++ 2 files changed, 43 insertions(+), 14 deletions(-)