SSE and FPU support #410
SSE and FPU support #410
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Addressed the review comments. |
kernel/src/cpu/sse.rs
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| // Check if at least SSE1 is supported | ||
| fn legacy_sse_supported() -> bool { | ||
| let Some(res) = cpuid_table_raw(1, 0, 0, 0) else { |
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This code needs to use the cpuid instruction directly to be compatible with the native and TD platform targets. I just realized there is no wrapper yet for cpuid, so please add one and use it for any FPU-related CPUID queries. This also affects other places in this PR.
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How about CpuidResult::get() which is also being used in places like kernel/src/platform/native.rs?
kernel/src/cpu/sse.rs
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| if extended_sse_supported() && xsave_supported() { | ||
| cr4_xsave_enable(); | ||
| xcr0_set(); | ||
| } else { | ||
| panic!("XSAVE is not supported by this hardware"); | ||
| } |
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| if extended_sse_supported() && xsave_supported() { | |
| cr4_xsave_enable(); | |
| xcr0_set(); | |
| } else { | |
| panic!("XSAVE is not supported by this hardware"); | |
| } | |
| if !extended_sse_supported() { | |
| panic!("Extended SSE is not supported by this hardware"); | |
| } | |
| if !xsave_supported() { | |
| panic!("XSAVE is not supported by this hardware"); | |
| } | |
| cr4_xsave_enable(); | |
| xcr0_set(); |
Make the panic messages a bit more concise.
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Sure, truncated them a bit.
kernel/src/task/schedule.rs
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| if !prev.is_null() { | ||
| sse_save_context(u64::from((*prev).xsa.vaddr())); | ||
| } | ||
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This can happen in schedule().
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moved to schedule()
kernel/src/task/schedule.rs
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| let cur = current_task(); | ||
| unsafe { | ||
| sse_restore_context(u64::from(cur.xsa.vaddr())); | ||
| } |
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This needs to be moved into the if let Some((current, next)) = work { branch. Otherwise the code will load an old FPU context when no context switch is happening.
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Ah, right! good point.
kernel/src/task/tasks.rs
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| unsafe { | ||
| sse_restore_context(xsa_addr); | ||
| } |
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This needs to be in setup_new_task().
| let xsa = Self::allocate_xsave_area(); | ||
| let xsa_addr = u64::from(xsa.vaddr()) as usize; | ||
| let (stack, raw_bounds, rsp_offset) = Self::allocate_ktask_stack(cpu, entry, xsa_addr)?; |
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The same needs to happen for user tasks.
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added to user tasks as well.
joergroedel
added
the
wait-for-update
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Addressed review comments. |
Some cpuid functions require a non-zero value of xcr0 to be passed. Signed-off-by: Vasant Karasulli <[email protected]>
Check for the available SSE/FPU related features and initialize them. Signed-off-by: Vasant Karasulli <[email protected]>
Reserve xsave area for tasks to manage xstate. Signed-off-by: Vasant Karasulli <[email protected]>
use xsaveopt/xrstor instructions to save and restore task context. Signed-off-by: Vasant Karasulli <[email protected]>
These in-svsm tests check if tasks can use some sse/fpu instructions and xstate is saved/restored properly during task switches. Signed-off-by: Vasant Karasulli <[email protected]>
This is a temporary solution until we have smart pointer. This also gives a chance to move xsave/xrestor functionality outside the assembly block. Signed-off-by: Vasant Karasulli <[email protected]>
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Rebase done. |
This PR entails following changes:
I will submit the related exception handling in another PR.